SOLUTION: 20x^2-21=-23x

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Question 606959: 20x^2-21=-23x
Answer by asuar010(338) 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 20x%5E2%2B23x%2B-21+=+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=%2823%29%5E2-4%2A20%2A-21=2209.

Discriminant d=2209 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-23%2B-sqrt%28+2209+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2823%29%2Bsqrt%28+2209+%29%29%2F2%5C20+=+0.6
x%5B2%5D+=+%28-%2823%29-sqrt%28+2209+%29%29%2F2%5C20+=+-1.75

Quadratic expression 20x%5E2%2B23x%2B-21 can be factored:
20x%5E2%2B23x%2B-21+=+20%28x-0.6%29%2A%28x--1.75%29
Again, the answer is: 0.6, -1.75. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+20%2Ax%5E2%2B23%2Ax%2B-21+%29