SOLUTION: -x^2-3x=-7

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Question 733113: -x^2-3x=-7
Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
a=-1, b=-3, c=7
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case -1x%5E2%2B-3x%2B7+=+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=%28-3%29%5E2-4%2A-1%2A7=37.

Discriminant d=37 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--3%2B-sqrt%28+37+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-3%29%2Bsqrt%28+37+%29%29%2F2%5C-1+=+-4.54138126514911
x%5B2%5D+=+%28-%28-3%29-sqrt%28+37+%29%29%2F2%5C-1+=+1.54138126514911

Quadratic expression -1x%5E2%2B-3x%2B7 can be factored:
-1x%5E2%2B-3x%2B7+=+-1%28x--4.54138126514911%29%2A%28x-1.54138126514911%29
Again, the answer is: -4.54138126514911, 1.54138126514911. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+-1%2Ax%5E2%2B-3%2Ax%2B7+%29