Question

Which statement is true concerning the vertex and the axis of symmetry of g(x)=5x2−10x?

The function written in vertex form is g(x)=5(x−1)2−5. The vertex is at (1, –5) and the axis of symmetry is x=1.
The vertex is at (1, –5) and the axis of symmetry is y = 1.
The vertex is at (0, 0) and the axis of symmetry is x = 1.
The vertex is at (0, 0) and the axis of symmetry is y = 1.

Answer 1

The first statement is true.

Work: g(x)=5x^2−10x = 5(x^2−2x) = 5[(x−1)^2−1] = 5(x−1)^2−5, so the vertex is (1, −5) and the axis of symmetry is x = 1.