SOLUTION: 2x² -3x -1 = 0

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Question 289355: 2x² -3x -1 = 0
Found 2 solutions by alegriajoy33, Deina:
Answer by alegriajoy33(14) About Me  (Show Source):
You can put this solution on YOUR website!
quadradic equation
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=2 b=-3 c=-1
so you get x=(4+-sqrt(17))/4
I hope you understand this.

Answer by Deina(147) 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-3x%2B-1+=+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=%28-3%29%5E2-4%2A2%2A-1=17.

Discriminant d=17 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--3%2B-sqrt%28+17+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-3%29%2Bsqrt%28+17+%29%29%2F2%5C2+=+1.78077640640442
x%5B2%5D+=+%28-%28-3%29-sqrt%28+17+%29%29%2F2%5C2+=+-0.280776406404415

Quadratic expression 2x%5E2%2B-3x%2B-1 can be factored:
2x%5E2%2B-3x%2B-1+=+2%28x-1.78077640640442%29%2A%28x--0.280776406404415%29
Again, the answer is: 1.78077640640442, -0.280776406404415. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-3%2Ax%2B-1+%29
and bob's your uncle!