SOLUTION: Solve using the quadratic formula 5x2-5x-10=0 note: the first 5x is squared but I wasn't sure how to put that in with the keyboard

Algebra ->  Test -> SOLUTION: Solve using the quadratic formula 5x2-5x-10=0 note: the first 5x is squared but I wasn't sure how to put that in with the keyboard      Log On


   

Question 509094: Solve using the quadratic formula
5x2-5x-10=0
note: the first 5x is squared but I wasn't sure how to put that in with the keyboard
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve using the quadratic formula
5x2-5x-10=0
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Use the ^ (Shift 6) for exponents
5x^2-5x-10=0
Divide by 5
x^2-x-2=0
(x-2)*(x+1) = 0
x = -1, 2
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 5x%5E2%2B-5x%2B-10+=+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=%28-5%29%5E2-4%2A5%2A-10=225.

Discriminant d=225 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--5%2B-sqrt%28+225+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-5%29%2Bsqrt%28+225+%29%29%2F2%5C5+=+2
x%5B2%5D+=+%28-%28-5%29-sqrt%28+225+%29%29%2F2%5C5+=+-1

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