SOLUTION: find the x intercepts of the parabola with vertex (-1,-16) and y intercept (0,-15). use equation (y-k)=a(x-h)^2

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: find the x intercepts of the parabola with vertex (-1,-16) and y intercept (0,-15). use equation (y-k)=a(x-h)^2      Log On


   



Question 1113240: find the x intercepts of the parabola with vertex (-1,-16) and y intercept (0,-15). use equation (y-k)=a(x-h)^2
Found 2 solutions by Fombitz, Boreal:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
%28y-k%29=a%28x-h%29%5E2
%28y-%28-16%29%29=a%28x-%28-1%29%29%5E2
y%2B16=a%28x%2B1%29%5E2
y=a%28x%2B1%29%5E2-16
When x=0,
-15=a%280%2B1%29%5E2-16
-15=a-16
a=1
So,
y%2B16=%28x%2B1%29%5E2
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So,
0%2B16=%28x%2B1%29%5E2
%28x%2B1%29%5E2=16
x%2B1=4 and x%2B1=-4
x=3 and x=-5
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Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
y=a(x-h)^2+k is the standard form, so h=-1 and k=-16
y=a(x+1)^2-16
putting (-1, -16) into vertex makes y+16=a(x+1)^2
x intercepts are where y=0. Where y=-15, x=0, so 1=a(1)^2. Therefore, a=1
a(x+1)^2=16
x+1=+/-4, since a=1
x=3, -5
(3, 0) and (-5, 0) ANSWER
The parabola is x^2+2x-15
That gives a vertex of (-1, -16) and the y-intercept of -15
graph%28300%2C300%2C-10%2C10%2C-20%2C20%2Cx%5E2%2B2x-15%29