Question

Write the equation of the parabola in vertex form.

vertex (2,1), point (1. - 1)

f(x) = 0

Answer 1

y = - 2(x - 2)² + 1

Explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Here (h, k) = (2, 1), thus

y = a(x - 2)² + 1

To find a substitute (1, - 1) into the equation

- 1 = a(1 - 2)² + 1 ( subtract 1 from both sides )

- 2 = a

y = - 2(x - 1)² + 1 ← in vertex form