Question

Find the equation of a parabola whose vertex is at (−1, 7), whose axis of symmetry is

x = −1, and whose y-intercept is (0, 10). Write your answer in vertex form.

Answer 1

Explanation:

The axis of symmetry is vertical, so the parabola is vertical.

Vertex-form equation for a vertical parabola with vertex (h,k):

y = a(x-h)² + k

axis of symmetry: x = h

Apply your data and solve for h, k, and a.

vertex (-1,7)

h = -1

k = 7

y = a(x+1)² + 7

(0,10) is a point on the parabola

10 = a(0+1)² + 7

a = 3

The equation becomes

y = 3(x+1)² + 7