Question 526143: How do I find the x-intercepts of the parabola with vertex (-3,16)and y-intercept (0,-20)
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! How do I find the x-intercepts of the parabola with vertex (-3,16)and y-intercept (0,-20)
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Standard equation for parabola: y=A(x-h)^2+k, with (h,k) being the (x,y) coordinates of the vertex.
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Given equation:
y=A(x+3)^2+16
using given point (0,-20) to solve for A
-20=A(0+3)^2+16
9A=-36
A=-4
Equation of parabola:
y=-4(x-h)^2+k
Find x-intercepts
set y=0
0=-4(x+3)^2+16
4(x+3)^2=16
(x+3)^2=4
x+3±√4=±2
x=-5
or
x=-1
Ans:
x-intercepts: -5 and -1
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