SOLUTION: Use the quadratic formula to solve the equation. 2y^2-2y=7

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Question 307123: Use the quadratic formula to solve the equation. 2y^2-2y=7
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Given: 2Y%5E2+-+2Y+=+7
Set the equation equal to zero
2Y%5E2+-+2Y+-+7+=+0
Use the quadratic equation
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ay%5E2%2Bby%2Bc=0 (in our case 2y%5E2%2B-2y%2B-7+=+0) has the following solutons:

y%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=%28-2%29%5E2-4%2A2%2A-7=60.

Discriminant d=60 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--2%2B-sqrt%28+60+%29%29%2F2%5Ca.

y%5B1%5D+=+%28-%28-2%29%2Bsqrt%28+60+%29%29%2F2%5C2+=+2.43649167310371
y%5B2%5D+=+%28-%28-2%29-sqrt%28+60+%29%29%2F2%5C2+=+-1.43649167310371

Quadratic expression 2y%5E2%2B-2y%2B-7 can be factored:
2y%5E2%2B-2y%2B-7+=+2%28y-2.43649167310371%29%2A%28y--1.43649167310371%29
Again, the answer is: 2.43649167310371, -1.43649167310371. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-2%2Ax%2B-7+%29