SOLUTION: Use the quadratic formula to solve the equation x^2+7x+9=0. The formula is: x=-b √b^2-4ac/2 please help

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Question 1016453: Use the quadratic formula to solve the equation x^2+7x+9=0.
The formula is: x=-b √b^2-4ac/2
please help
Answer by macston(5194) 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%2B7x%2B9+=+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=%287%29%5E2-4%2A1%2A9=13.

Discriminant d=13 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-7%2B-sqrt%28+13+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%287%29%2Bsqrt%28+13+%29%29%2F2%5C1+=+-1.69722436226801
x%5B2%5D+=+%28-%287%29-sqrt%28+13+%29%29%2F2%5C1+=+-5.30277563773199

Quadratic expression 1x%5E2%2B7x%2B9 can be factored:
1x%5E2%2B7x%2B9+=+1%28x--1.69722436226801%29%2A%28x--5.30277563773199%29
Again, the answer is: -1.69722436226801, -5.30277563773199. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B7%2Ax%2B9+%29