SOLUTION: Solve each equation by using the quadratic formula. -9d-3d^2=5

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Question 526675: Solve each equation by using the quadratic formula.
-9d-3d^2=5
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ad%5E2%2Bbd%2Bc=0 (in our case -3d%5E2%2B-9d%2B-5+=+0) has the following solutons:

d%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-9%29%5E2-4%2A-3%2A-5=21.

Discriminant d=21 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--9%2B-sqrt%28+21+%29%29%2F2%5Ca.

d%5B1%5D+=+%28-%28-9%29%2Bsqrt%28+21+%29%29%2F2%5C-3+=+-2.26376261582597
d%5B2%5D+=+%28-%28-9%29-sqrt%28+21+%29%29%2F2%5C-3+=+-0.736237384174027

Quadratic expression -3d%5E2%2B-9d%2B-5 can be factored:
-3d%5E2%2B-9d%2B-5+=+-3%28d--2.26376261582597%29%2A%28d--0.736237384174027%29
Again, the answer is: -2.26376261582597, -0.736237384174027. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+-3%2Ax%5E2%2B-9%2Ax%2B-5+%29