Question

Enter an equation for the line of symmetry for the function f (x) = 5x^2 – 20x + 3.

Answer 1

x = 2.

Explanation:

First convert to vertex form:

f(x) = 5x^2 - 20x + 3

= 5(x^2 - 4x) + 3

= 5 [(x - 2)^2 - 4] + 3

= 5(x - 2)^2 -20 + 3

= 5(x - 2)^2 - 17.

The line of symmetry is x = 2.