SOLUTION: all our teacher gave us is a worksheet and it says "Sove each equation. Check your solution." here is one of many problems: xsquared + 10x + 9 = 0. please and thank you.

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: all our teacher gave us is a worksheet and it says "Sove each equation. Check your solution." here is one of many problems: xsquared + 10x + 9 = 0. please and thank you.      Log On


   

Question 21995: all our teacher gave us is a worksheet and it says "Sove each equation. Check your solution." here is one of many problems: xsquared + 10x + 9 = 0. please and thank you.
Answer by Alwayscheerful(414) 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%2B10x%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=%2810%29%5E2-4%2A1%2A9=64.

Discriminant d=64 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-10%2B-sqrt%28+64+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2810%29%2Bsqrt%28+64+%29%29%2F2%5C1+=+-1
x%5B2%5D+=+%28-%2810%29-sqrt%28+64+%29%29%2F2%5C1+=+-9

Quadratic expression 1x%5E2%2B10x%2B9 can be factored:
1x%5E2%2B10x%2B9+=+1%28x--1%29%2A%28x--9%29
Again, the answer is: -1, -9. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B10%2Ax%2B9+%29

Hope this helps!