SOLUTION: y squared minus 8y minus 2 equals 0

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Question 920628: y squared minus 8y minus 2 equals 0
Answer by srinivas.g(540) About Me  (Show Source):
You can put this solution on YOUR website!
y^2-8y-2 =0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ay%5E2%2Bby%2Bc=0 (in our case 1y%5E2%2B-8y%2B-2+=+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=%28-8%29%5E2-4%2A1%2A-2=72.

Discriminant d=72 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--8%2B-sqrt%28+72+%29%29%2F2%5Ca.

y%5B1%5D+=+%28-%28-8%29%2Bsqrt%28+72+%29%29%2F2%5C1+=+8.24264068711928
y%5B2%5D+=+%28-%28-8%29-sqrt%28+72+%29%29%2F2%5C1+=+-0.242640687119285

Quadratic expression 1y%5E2%2B-8y%2B-2 can be factored:
1y%5E2%2B-8y%2B-2+=+1%28y-8.24264068711928%29%2A%28y--0.242640687119285%29
Again, the answer is: 8.24264068711928, -0.242640687119285. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-8%2Ax%2B-2+%29