SOLUTION: write an equation of the parabola that passes through the point (3,-30) and has x-intercepts -2 and 18.

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Question 1003837: write an equation of the parabola that passes through the point (3,-30) and has x-intercepts -2 and 18.
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
write an equation of the parabola that passes through the point (3,-30) and has x-intercepts -2 and 18.
x=-2, x=18

x%2B2=0,  x-18=0

y+=+a%28x%2B2%29%28x-18%29

y+=+a%28x%5E2-16x-36%29

Substitute (x,y) = (3,-30)

-30+=+a%283%5E2-16%2A3-36%29

-30+=+a%289-48-36%29

-30+=+a%28-75%29

%28-30%29%2F%28-75%29=a

2%2F5=a

So the equation 

y+=+a%28x%5E2-16x-36%29

becomes:

y+=+expr%282%2F5%29%28x%5E2-16x-36%29

y+=+expr%282%2F5%29x%5E2-expr%2832%2F5%29x-expr%2872%2F5%29%29

Edwin


Edwin