SOLUTION: what would the answer be for thi x^2+13x=45

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Question 365184: what would the answer be for thi x^2+13x=45
Answer by JBarnum(2146) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B13x%2B-45+=+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=%2813%29%5E2-4%2A1%2A-45=349.

Discriminant d=349 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-13%2B-sqrt%28+349+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2813%29%2Bsqrt%28+349+%29%29%2F2%5C1+=+2.8407708461347
x%5B2%5D+=+%28-%2813%29-sqrt%28+349+%29%29%2F2%5C1+=+-15.8407708461347

Quadratic expression 1x%5E2%2B13x%2B-45 can be factored:
1x%5E2%2B13x%2B-45+=+1%28x-2.8407708461347%29%2A%28x--15.8407708461347%29
Again, the answer is: 2.8407708461347, -15.8407708461347. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B13%2Ax%2B-45+%29