Question

Find the x-intercepts if the parabola with vertex (-3,-18) and y-intercept (0,0). Write your answer

Answer 1

Vertex form is 
y = a(x - b)^2 + c

here a = -3 and b = -18 so we have

y = a(x + 3)^2 - 18

when x = 0 , y= 0  ( the y-intercept) so:-

0 = a(3^)2 - 18
9a = 18 
a = 2

so the parabola  is y = 2(x + 3)^2 - 18

x intercepts found as follows:-

2(x + 3)^2 - 18 = 0
(x + 3)^2 = 9
x + 3 =  +/- sqrt9  = +/- 3

so x intercepts  are 0 and -6 Answer