SOLUTION: find the x-intercepts of the parabola with vertex (-3,16) and y-intercept (0,-20).

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Question 963559: find the x-intercepts of the parabola with vertex (-3,16) and y-intercept (0,-20).
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
In vertex form,
y=a%28x%2B3%29%5E2%2B16
Use the y-intercept,
-20=a%280%2B3%29%5E2%2B16
-20=9a%2B16
9a=-36
a=-4
So then,
y=-4%28x%2B3%29%5E2%2B16
For x-intercepts, set y=0 and solve for x,
0=-4%28x%2B3%29%5E2%2B16
4%28x%2B3%29%5E2=16
%28x%2B3%29%5E2=4
x%2B3=0+%2B-+2
x=3+%2B-+2
x=1 and x=5
(1,0) and (5,0)