SOLUTION: 3=x(2x+9)

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Question 864077: 3=x(2x+9)
Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
3=x(2x+9)
2x^2+9x-2=0

Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B9x%2B-2+=+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=%289%29%5E2-4%2A2%2A-2=97.

Discriminant d=97 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-9%2B-sqrt%28+97+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%289%29%2Bsqrt%28+97+%29%29%2F2%5C2+=+0.212214450449026
x%5B2%5D+=+%28-%289%29-sqrt%28+97+%29%29%2F2%5C2+=+-4.71221445044903

Quadratic expression 2x%5E2%2B9x%2B-2 can be factored:
2x%5E2%2B9x%2B-2+=+2%28x-0.212214450449026%29%2A%28x--4.71221445044903%29
Again, the answer is: 0.212214450449026, -4.71221445044903. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B9%2Ax%2B-2+%29