SOLUTION: 2b to the 2 power -15b -7 =0

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Question 302443: 2b to the 2 power -15b -7 =0
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
2b^2-15b-7=0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ab%5E2%2Bbb%2Bc=0 (in our case 2b%5E2%2B-15b%2B-7+=+0) has the following solutons:

b%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=%28-15%29%5E2-4%2A2%2A-7=281.

Discriminant d=281 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--15%2B-sqrt%28+281+%29%29%2F2%5Ca.

b%5B1%5D+=+%28-%28-15%29%2Bsqrt%28+281+%29%29%2F2%5C2+=+7.94076365356005
b%5B2%5D+=+%28-%28-15%29-sqrt%28+281+%29%29%2F2%5C2+=+-0.440763653560053

Quadratic expression 2b%5E2%2B-15b%2B-7 can be factored:
2b%5E2%2B-15b%2B-7+=+2%28b-7.94076365356005%29%2A%28b--0.440763653560053%29
Again, the answer is: 7.94076365356005, -0.440763653560053. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-15%2Ax%2B-7+%29