Put everything together: factor first, then move points
Think of moving a printed map after changing its size on a copier. First you resize it around the original axes. Then you slide it to its new location. Reversing those jobs can resize the slide too, so the order matters. A Sequence of transformations is a set of changes performed in a stated order. The expression a·f(b(x − h)) + k keeps the jobs visible: resize or reflect the horizontal coordinates, slide them, resize or reflect the heights, then lift them. If the inside arrives as 2x − 6, use Factoring to rewrite it as 2(x − 3). That shows the final sideways slide is three, not six.
- Factoring every inside term. Divide both terms by the same coefficient: 2x − 6 = 2(x − 3). Distributing 2 back into the parentheses recovers 2x − 6.
- Dividing by a signed fraction. For b = , u ÷ b = 2u. For b = −2, 4 ÷ b = −2. The signed division handles width and reflection together.
- Outside arithmetic order. For old height 5 in −2f(x + 1) + 3, calculate −2 × 5 + 3 = −10 + 3 = −7. The final addition follows multiplication.
- The square root restriction. A real square root requires a nonnegative inside. For −2(x + 4) ≥ 0, divide by −2 to find allowed inputs, reverse the comparison, and subtract 4: x ≤ −4. At −4, the inside is 0.
- Extracting a square factor. Keep exact roots: = = 2, because (2 = 8 and 2 is nonnegative.
Resize or reflect each coordinate first, then move it to its final address. Factoring makes the horizontal slide visible.
In g(x) = a·f(b(x − h)) + k, an old point (u, v) moves to horizontal coordinate u ÷ b + h and height a·v + k, with b ≠ 0.
- b(X − h) = u gives X = + h. Y = a·v + k.
- (u, v) becomes ( + h, a·v + k).
- bx + c = b(x + ), so h = −, with b ≠ 0.
- Graph words: scale or reflect horizontally, shift horizontally; scale or reflect vertically, shift vertically.
Resize a printed map around its original axes, then slide the resized map into its final position.
The old square graph first flips downward and doubles its heights. Then its old lowest point at (0, 0) moves to (3, 4). The new graph opens down because the coefficient of its heights is negative.
Horizontal address: divide, then add. Height: multiply, then add. For old point (2, 5) and −2f(x + 1) + 3, these jobs give 2 − 1 = 1 and −2·5 + 3 = −7.
Set the inside expression equal to old input u. The equation b(x − h) = u gives x = u ÷ b + h. Once f receives u, it produces old output v, and the remaining outside work produces av + k.
Start with old height 1. Double and then add 3: 2·1 + 3 = 5. Add 3 and then double: 2(1 + 3) = 8. The slide is doubled in the second calculation, which is why the order cannot be swapped on the same coordinate.
Factor, divide, multiply, then shift. Factoring exposes h. Divide the horizontal coordinate by b; multiply the height by a. Shift each coordinate after its scale. Keep the one-page table handy while learning and rebuild the point rule from its equation.
| Put on the cheat sheet | Coordinate effect or check |
|---|---|
| f(x) + k | (u, v) to (u, v + k) |
| f(x − h) | (u, v) to (u + h, v) |
| −f(x) | (u, v) to (u, −v), reflection across x-axis |
| f(−x) | (u, v) to (−u, v), reflection across y-axis |
| a·f(x), a ≠ 0 | Height factor |a|; reflect vertically when a < 0 |
| f(bx), b ≠ 0 | Width factor ; reflect horizontally when b < 0 |
| a·f(b(x − h)) + k | (u, v) to ( + h, a·v + k) |
| bx + c = b(x + ) | Final horizontal shift h = − |
| Even function | Symmetric domain and f(−x) = f(x) |
| Odd function | Symmetric domain and f(−x) = −f(x) |
| Require b(x − h) ≥ 0 | |
| Require b(x − h) ≠ 0 |
.1Factor the inside
Pull the multiplier on x outside the entire parentheses. Like sorting equal bundles, divide every inside term by the same number so the expression keeps its value.
- 2x − 6 = 2(x − 3), because 2·3 = 6.
- The final shift is right 3 when the inside is 2(x − 3).
- In bx + c, b ≠ 0, the final horizontal shift is −.
- If b = 0, the inside no longer varies with x; the usual point rule does not apply.
Describe f(2x − 6).
This asks which horizontal resizing and shift are encoded in the given input expression. Factor it to reveal both changes.
- Rewrite 2x − 6 as 2(x − 3).Dividing both terms by 2 leaves x − 3 inside.
- Read b = 2 and h = 3.The factored form matches b(x − h).
- Compress the horizontal coordinates by , then shift right 3.New x is old x ÷ 2 + 3.
- Use the displayed landmark or known column as a check before drawing any additional points.
.2Move the horizontal coordinate
Recover the old input before thinking about the height. A negative divisor reverses left and right; then the shift carries the already resized coordinate to its final address.
- New horizontal coordinate: X = + h.
- When b < 0, divide with its sign and then add h.
- The alternative unfactored equation bx + c = u gives the same X.
- Do not add h before dividing unless you have correctly adjusted the formula.
Old point (4, 1) is on f. Move it to f(2x − 6).
This asks you to find the new address or height of the given graph information.
- Solve 2X − 6 = 4.The old output 1 belongs to old input 4.
- Add 6: 2X = 10. Divide by 2: X = 5.Undo subtraction and multiplication in order.
- Keep output 1.There is no outside change.
- Use the displayed landmark or known column as a check before drawing any additional points.
.3Move the vertical coordinate
After the old function gives its height, the outside operations finish the job. Multiply that height, including any sign, and then add the final lift.
- New vertical coordinate: Y = a·v + k.
- If a < 0, reflect vertically and scale by |a| before shifting.
- If a = 0, every permitted input has output k; this is a collapse, not an ordinary stretch.
- The domain of the expression still requires its inner function to be defined.
For old height 5, find the new height in −2f(x + 1) + 3.
This asks you to find the new address or height of the given graph information.
- Multiply 5 by −2 to get −10.The outside coefficient reflects and doubles the height.
- Add 3 to get −7.The upward shift follows the multiplication.
- Use the displayed landmark or known column as a check before drawing any additional points.
.4Build and sketch the whole graph
Choose landmarks from a familiar shape, move them using both coordinate jobs, and keep the original connections. A shifted endpoint or corner gives the graph an anchor.
- The vertex of a·(x − h + k is (h, k) when a ≠ 0.
- Positive a opens the quadratic up; negative a opens it down.
- For a < 0, the largest quadratic height is k, so its range is y ≤ k.
- Horizontal and vertical work can be interleaved, as long as each coordinate keeps its own scale-before-shift order.
Move the old square points (−1, 1), (0, 0), (1, 1) to −2(x − 3 + 4.
This asks you to find the new address or height of the given graph information.
- Add 3 to each old horizontal coordinate: 2, 3, 4.The inside x − 3 shifts the graph right 3.
- Transform heights 1, 0, 1 using −2v + 4 to get 2, 4, 2.The outside reflection and stretch occur before the upward shift.
- Draw a downward-opening quadratic through (2, 2), (3, 4), (4, 2).The negative height coefficient reverses the original opening.
- Points: (2, 2), (3, 4), (4, 2).
- Vertex: (3, 4).
Vertex: (3, 4).
- Use the displayed landmark or known column as a check before drawing any additional points.
- 1. Recognize f and its domain, range, and landmarks.
- 2. Factor the entire input into b(x − h). Distribute it back out to verify the factoring.
- 3. Label a, b, h, and k, keeping every sign.
- 4. For each old point (u, v), compute new x = u ÷ b + h.
- 5. Compute new y = a·v + k. Multiply before adding because that is the outside formula's order.
- 6. Move at least three points and any asymptotes or endpoints; draw the transformed shape.
- 7. Find the new domain from b(x − h) belonging to the old domain, and the new range from a·v + k over old range values.
- 8. Substitute a moved point into the original unfactored formula as a second check.
Factor and transform a whole graph or table
- 1. Name the original Function and its available points. Record restrictions before moving the graph so a forbidden input cannot become a supplied value.
- 2. Factor the inside into b(x − h), with b ≠ 0. This reveals the shift after the horizontal scale; 2x − 6 = 2(x − 3) identifies b = 2 and h = 3. Distribute to check the rewrite.
- 3. Solve b(X − h) = u for each old input u. This finds where its old output appears: divide by b and add h to obtain X = + h.
- 4. Compute Y = a·v + k from its matching old output v. This applies the outside scale before the final shift.
- 5. Move landmarks and several other points, or build the transformed table column by column. Keep every old input paired with its own old output.
- 6. Rebuild the Domain from the inner restrictions and the Range from the transformed heights. For −2(x − 3 + 4, all inputs remain allowed and the nonnegative square shows that heights cannot exceed 4; the vertex reaches 4.
- 7. Check using the original expression. For old point (4, 1) and g(x) = f(2x − 6), new input 5 gives g(5) = f(4) = 1, confirming the moved point.
Start with . Reflect across the x-axis, stretch vertically by 2, move right 3, and move up 4. Write the formula and sketch the graph.
This asks you to write the new rule from the specified moves and check its graph landmarks.
- Reflect and stretch with coefficient a = −2: −2.The negative sign reverses heights and magnitude 2 doubles their distances from the original x-axis.
- Replace x with x − 3: −2(x − 3.A rightward shift needs new inputs three larger to reproduce the old inputs.
- Add 4 outside: g(x) = −2(x − 3 + 4.The final upward shift raises the already reflected and stretched heights.
- Move (0, 0) to (3, 4), (1, 1) to (4, 2), and (−1, 1) to (2, 2).New x = u + 3 and new y = −2v + 4.
- Domain is all real numbers and range is y ≤ 4.Squaring accepts all real inputs, and −2(x − 3 ≤ 0 gives a maximum height of 4.
- g(x) = −2(x − 3 + 4.
- Vertex: (3, 4).
- Opening: downward.
- g(4) = 2.
- Domain: (−∞, ∞).
- Range: (−∞, 4].
The point (2, 5) is on f. Where does it go on g(x) = −2f(x + 1) + 3?
This asks you to find the new address or height of the given graph information.
- Solve X + 1 = 2, giving X = 1.The input inside f must recover old input 2.
- Compute Y = −2·5 + 3 = −10 + 3 = −7.Multiply the old height before adding the outside shift.
Describe g(x) = f(2x − 6) and move old point (4, 1).
This asks you to find the new address or height of the given graph information.
- Factor 2x − 6 = 2(x − 3).The coefficient on x multiplies the whole parentheses.
- Read b = 2 and h = 3.The factored expression is in the standard input form.
- Compute new X = 4 ÷ 2 + 3 = 5 and keep Y = 1.Divide the horizontal coordinate first, then shift it; there is no outside change.
- Compress horizontally by , then shift right 3.
- (4, 1) becomes (5, 1).
Create the table for g(x) = 2f(3x) + 1. Use the original f table displayed beside this question.
This asks you to attach each known output to its transformed input and calculate any requested new height.
- Read the displayed original table column by column. Each top input belongs to the output directly below it.The picture supplies the known values used in the following calculations; keep each column paired.
- Divide inputs by 3: 2, 4, 6, 8.3X must equal each old input.
- Double outputs: 20, 28, 30, 34.The outside coefficient 2 stretches the old heights.
- Add 1 to the doubled outputs: 21, 29, 31, 35.The final vertical shift follows the stretch.
- Use the displayed transformed table
- each column records one new input and its corresponding output.
The graph of f contains (0, 2) and (2, 0). Move these points to g(x) = f(x + 1) − 3.
This asks you to find the new address or height of the given graph information.
- Factor x + 1 = (x + 2).Multiplying by 2 returns the original constant 1.
- Use b = , h = −2, a = 1, k = −3.x + 2 is x − (−2).
- Stretch horizontal coordinates by 2: (0, 2) stays (0, 2), while (2, 0) becomes (4, 0).Divide old inputs by .
- Shift left 2: the points become (−2, 2) and (2, 0).Add h = −2 after the horizontal scaling.
- Shift down 3: the points become (−2, −1) and (2, −3).Subtract 3 from the heights after the horizontal work.
- Horizontal stretch by 2, then left 2, then down 3.
- (0, 2) becomes (−2, −1).
- (2, 0) becomes (2, −3).
Reflect across the x-axis, stretch it vertically by 2, then move it right 3 and up 4.
This asks you to write the new rule from the specified moves and check its graph landmarks.
- Use −2 to reflect and stretch the original heights.The sign gives the flip and the magnitude gives the scale.
- Use x − 3 inside squaring and add 4 after multiplying: g(x) = −2(x − 3 + 4.The horizontal shift is undone inside; the final vertical shift changes the completed height.
- Find g(3) = 4 and g(4) = 2.The vertex uses zero inside and a neighboring point uses one inside.
- g(x) = −2(x − 3 + 4.
- Vertex: (3, 4).
- Opening: downward.
- g(4) = 2.
Starting from f(x) = , graph g(x) = −3 + 5. Move old points (0, 0), (1, 1), (4, 2), and (8, 2). State its domain and range.
This asks you to find the new address or height of the given graph information.
- Read a = −3, b = −2, h = −4, and k = 5.x + 4 equals x − (−4), so the factored input already exposes the shift.
- Use X = u ÷ (−2) − 4 and Y = −3v + 5.The point rule divides and shifts the horizontal coordinate, then multiplies and shifts the height.
- Move (0, 0) to (−4, 5). Move (1, 1) to (−, 2).0 ÷ (−2) − 4 = −4; 1 ÷ (−2) − 4 = − − = −. Heights are 5 and 2.
- Move (4, 2) to (−6, −1) and (8, 2) to (−8, 5 − 6).4 ÷ (−2) − 4 = −6 and 8 ÷ (−2) − 4 = −8. Apply −3v + 5 to each old height.
- Solve −2(x + 4) ≥ 0. Dividing by −2 reverses the inequality: x + 4 ≤ 0, so x ≤ −4.The radicand must be nonnegative, and multiplying an inequality by a negative reverses its order.
- The range is y ≤ 5.The nonnegative root is multiplied by −3, producing nonpositive values, then raised by 5; unbounded roots give arbitrarily low heights.
- Endpoint: (−4, 5).
- Other points: (−, 2), (−6, −1), (−8, 5 − 6).
- Domain: (−∞, −4].
- Range: (−∞, 5].
- Write a, b, h, and k beside the factored formula before moving any point. Include each negative sign.
- Use two lines for the point work: new x = old x ÷ b + h, and new y = a·old y + k.
- Factor, divide, multiply, then shift is a memory cue. Keep each coordinate's scaling before its shift; horizontal and vertical work can be done independently.
- Check a moved point in the original unfactored input. This can catch both a factoring error and a reversed transformation order.
- Track a corner, endpoint, or asymptote and more than one other point. A few supplied dots determine those dots' new positions, while a complete sketch also requires the original graph's shape.