Question

The graph shows the axis of symmetry for a quadratic function f(x).

On a coordinate plane, a vertical dashed line at (4, 0) is parallel to the y-axis.
Which could be the function?

f(x) = (x + 4)2
f(x) = x2 + 4
f(x) = (x – 4)2
f(x) = x2 – 4

Answer 1

f(x) = (x − 4)^2

Reason: A parabola (x − h)^2 + k has axis x = h. (x − 4)^2 has axis x = 4. The others have axes x = −4 or x = 0.