SOLUTION: 2xsquared + 11x = 121 I have simplified my problem to this point and can't remember how to simply it further to get the value of x. i would appreciate your help. Thanks Bill

Algebra ->  Equations -> SOLUTION: 2xsquared + 11x = 121 I have simplified my problem to this point and can't remember how to simply it further to get the value of x. i would appreciate your help. Thanks Bill      Log On


   

Question 966043: 2xsquared + 11x = 121
I have simplified my problem to this point and can't remember how to simply it further to get the value of x.
i would appreciate your help.
Thanks
Bill
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
2x^2 + 11x = 121
2x^2 + 11x - 121 = 0
---
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B11x%2B-121+=+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=%2811%29%5E2-4%2A2%2A-121=1089.

Discriminant d=1089 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-11%2B-sqrt%28+1089+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2811%29%2Bsqrt%28+1089+%29%29%2F2%5C2+=+5.5
x%5B2%5D+=+%28-%2811%29-sqrt%28+1089+%29%29%2F2%5C2+=+-11

Quadratic expression 2x%5E2%2B11x%2B-121 can be factored:
2x%5E2%2B11x%2B-121+=+%28x-5.5%29%2A%28x--11%29
Again, the answer is: 5.5, -11. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B11%2Ax%2B-121+%29