SOLUTION: X^2+9x=20 divided by x+4

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Question 1034064: X^2+9x=20 divided by x+4
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
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x%5E2%2B9x=20 / %28x%2B4%29
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%28x%5E2%2B9x%29%2F%28x%2B4%29=%2820%2F%28x%2B4%29%29 Multiply both sides by (x+4)
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x%5E2%2B9x=20
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x%5E2%2B9x-20=0
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B9x%2B-20+=+0) has the following solutons:

x%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=%289%29%5E2-4%2A1%2A-20=161.

Discriminant d=161 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-9%2B-sqrt%28+161+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%289%29%2Bsqrt%28+161+%29%29%2F2%5C1+=+1.84428877022476
x%5B2%5D+=+%28-%289%29-sqrt%28+161+%29%29%2F2%5C1+=+-10.8442887702248

Quadratic expression 1x%5E2%2B9x%2B-20 can be factored:
1x%5E2%2B9x%2B-20+=+1%28x-1.84428877022476%29%2A%28x--10.8442887702248%29
Again, the answer is: 1.84428877022476, -10.8442887702248. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B9%2Ax%2B-20+%29

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I think perhaps you mis-worded your question.
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