Answer:
The image of point (2, 4) after transformation is (-2, 13) ⇒ D
Step-by-step explanation:
Let us revise some transformation
Translation right-left OR up-down
- If the function f(x) translated horizontally to the right by h units, then its image is g(x) = f(x - h) ⇒ add x-coordinate of every point by h
- If the function f(x) translated horizontally to the left by h units, then its image is g(x) = f(x + h)
⇒ subtract x-coordinate of every point by h
- If the function f(x) translated vertically up by k units, then its image is g(x) = f(x) + k ⇒ add y-coordinate of every point by k
- If the function f(x) translated vertically down by k units, then its image is g(x) = f(x) - k ⇒ subtract y-coordinate of every point by k
A vertical stretching and a vertical compression (or shrinking)
- If m > 1, the graph of y = m • f(x) is the graph of f(x) vertically stretched by factor m. ⇒ multiply every y-coordinate by m
- If 0 < m < 1 (a fraction), the graph of y = m • f(x) is the graph of f(x) vertically shrunk (or compressed) by factor m ⇒ multiply every y-coordinate by m
Let us use these rules to solve the question.
∵ Point (2, 4) lies on y = x²
∵ The image of y = x² is y = 3(x + 4)²+1
→ The rules of transformation is y = m(x + h)² + k
∵ m is the scale factor of a vertical stretched
∵ m = 3
→ By using the 5th rule above
∴ The y-coordinate of point (2, 4) should multiply by 3
∴ The image of the point is (2, 4 × 3) = (2, 12)
∵ h is the horizontal translation to the left
∵ h = 4
→ By using the 2nd rule above
∴ The x-coordinate of point (2, 12) should subtract by 4
∴ The image of the point is (2 - 4, 12) = (-2, 12)
∵ k is the vertical translation up
∵ k = 1
→ By using the 3rd rule above
∴ The y-coordinate of point (-2, 12) should add by 1
∴ The image of the point is (-2, 12 + 1) = (-2, 13)
∴ The image of point (2, 4) after transformation is (-2, 13)
