Question

A quadratic function y=f(x)y=f(x) is plotted on a graph and the vertex of the resulting parabola is (-4, -5)(−4,−5). What is the vertex of the function defined as g(x)=f(x+2)+3g(x)=f(x+2)+3?

Answer 1

The vertex of the function g(x) = f(x + 2) + 3 is (-6, -2)

Explanation:

• If the graph of the function f(x) is translated h units to the left, then its image g(x) = f(x + h)

• If the graph of the function f(x) is translated k units up, then its image g(x) = f(x) + k

Let us use these facts above to solve the question

∵ The quadratic function f(x) = y has a vertex point (-4, -5)

∵ g(x) = f(x + 2) + 3

→ By using the two facts above

∴ f(x) is translated 2 units to the left

∴ f(x) is translated 3 units up

→ That means the vertex point must move 2 units left and 3 units up

∵ The rule of translation is T (x, y) → (x - 2, y + 3)

∵ The coordinates of the vertex point of f(x) are (-4, -5)

∴ Its image is (-4 - 2, -5 + 3)

∴ Its image is (-6, -2)

∴ The vertex of the function g(x) = f(x + 2) + 3 is (-6, -2)