SOLUTION: 2x^2-9x-9 grrr this was given to my little brother as homework who is 2 years younger than me i havnt done quadratic eqautions for ages please help

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Question 42496: 2x^2-9x-9 grrr this was given to my little brother as homework who is 2 years younger than me i havnt done quadratic eqautions for ages please help
Answer by askmemath(368) 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 2x%5E2%2B-9x%2B-9+=+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=%28-9%29%5E2-4%2A2%2A-9=153.

Discriminant d=153 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--9%2B-sqrt%28+153+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-9%29%2Bsqrt%28+153+%29%29%2F2%5C2+=+5.34232921921325
x%5B2%5D+=+%28-%28-9%29-sqrt%28+153+%29%29%2F2%5C2+=+-0.842329219213245

Quadratic expression 2x%5E2%2B-9x%2B-9 can be factored:
2x%5E2%2B-9x%2B-9+=+2%28x-5.34232921921325%29%2A%28x--0.842329219213245%29
Again, the answer is: 5.34232921921325, -0.842329219213245. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-9%2Ax%2B-9+%29