Question

What is the axis of symmetry for f(x)=-2x^2+20x-42

Answer 1

f(x) = -2x² + 20x - 42

This is a quadratic expression.

For a general expression ax² + bx + c, the axis of symmetry x = -b/2a

Comparing -2x² + 20x - 42 to ax² + bx + c, a = -2, b = 20, c= -42

Axis of symmetry, x = -b/2a

x = -20 / (2 * -2) = -20/-4 = 5

Therefore axis of symmetry is x = 5.