SOLUTION: x(x-2)=4

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Question 163304: x(x-2)=4
Found 2 solutions by jojo14344, Fombitz:
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
x%28x-2%29=4
x%5E2-2x=4
x%5E2-2x-4=0
Remember: a=1%2Cb=-2%2C+c=-4
By Pyth. theorem:
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x=%28-%28-2%29%2B-sqrt%28-2%5E2-4%2A1%2A-4%29%29%2F%282%2A1%29
x=%282%2B-sqrt%284%2B16%29%29%2F2
x=%282%2B-sqrt%2820%29%29%2F2
2 values:
x=%282%2Bsqrt%2820%29%29%2F2=%282%2B4.472136%29%2F2=6.472136%2F2
highlight%28x=3.236068%29
x=%282-sqrt%2820%29%29%2F2=%282-4.72136%29%2F2=-2.472136%2F2
x=-1.236068
Check it out,x=3.236068
3.236068%283.236068-2%29=4
3.236068%281.236068%29=4
4.000000001=4 close enough! bec of decimals
Thank you,
Jojo

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
x%28x-2%29=4
x%5E2-2x=4
x%5E2-2x-4=0
Use the quadratic formula,
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-%28-2%29+%2B-+sqrt%28+%28-2%29%5E2-4%2A1%2A%28-4%29+%29%29%2F%282%2A1%29+
x+=+%282+%2B-+sqrt%28+4%2B16+%29%29%2F%282%29+
x+=+%282+%2B-+sqrt%2820+%29%29%2F%282%29+
or approximately
x%5B1%5D=%282%2B4.47%29%2F2=3.235
x%5B2%5D=%282-4.47%29%2F2=-1.235