SOLUTION: Solve the equation. (y-3) (y+7)=0

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Question 80479: Solve the equation. (y-3) (y+7)=0
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
(y-3)(y+7)=0
y^2-3y+7y-21=0
y^2+4y-21=0
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one way to check his is to use the quadratic equation ay^2+by+c:
y+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
then you'll see that:
y-3=0
y=3
&
y+7=0
y=-7