SOLUTION: how do u slove -b + square root b to the second power subtract 4ac over 2a to slove n to the second power subtract 8n-4=0? using the quadratic formula step by step??

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Question 48139: how do u slove -b + square root b to the second power subtract 4ac over 2a to slove n to the second power subtract 8n-4=0? using the quadratic formula step by step??
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
n^2- 8n -4=0
n=[8+-sqrt(64-4(-4)/2
n=[8+-sqrt80]/2
n=[8+-4sqrt(5)]/2
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation an%5E2%2Bbn%2Bc=0 (in our case 1n%5E2%2B-8n%2B-4+=+0) has the following solutons:

n%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-4=80.

Discriminant d=80 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--8%2B-sqrt%28+80+%29%29%2F2%5Ca.

n%5B1%5D+=+%28-%28-8%29%2Bsqrt%28+80+%29%29%2F2%5C1+=+8.47213595499958
n%5B2%5D+=+%28-%28-8%29-sqrt%28+80+%29%29%2F2%5C1+=+-0.47213595499958

Quadratic expression 1n%5E2%2B-8n%2B-4 can be factored:
1n%5E2%2B-8n%2B-4+=+1%28n-8.47213595499958%29%2A%28n--0.47213595499958%29
Again, the answer is: 8.47213595499958, -0.47213595499958. 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-4+%29


Hope this helps.
Cheers,
Stan H.