SOLUTION: 8n^2-4n=18 I am really confused :(

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Question 664042: 8n^2-4n=18
I am really confused :(
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
First get the equation into standard form

8n%5E2-4n=18

8n%5E2-4n-18=18-18

8n%5E2-4n-18=0

Now use the quadratic formula to solve for n

n+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29

n+=+%28-%28-4%29%2B-sqrt%28%28-4%29%5E2-4%288%29%28-18%29%29%29%2F%282%288%29%29

n+=+%284%2B-sqrt%2816-%28-576%29%29%29%2F%2816%29

n+=+%284%2B-sqrt%2816%2B576%29%29%2F%2816%29

n+=+%284%2B-sqrt%28592%29%29%2F16

n+=+%284%2Bsqrt%28592%29%29%2F16 or n+=+%284-sqrt%28592%29%29%2F16

n+=+%284%2B4%2Asqrt%2837%29%29%2F16 or n+=+%284-4%2Asqrt%2837%29%29%2F16

n+=+%281%2Bsqrt%2837%29%29%2F4 or n+=+%281-sqrt%2837%29%29%2F4

n+=+1.77069 or n+=+-1.27069

So the exact solutions are n+=+%281%2Bsqrt%2837%29%29%2F4 or n+=+%281-sqrt%2837%29%29%2F4

and the approximate solutions are n+=+1.77069 or n+=+-1.27069