SOLUTION: Solve: 8(3x+5)^2 +2(3x+5)-1=0

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Question 381285: Solve: 8(3x+5)^2 +2(3x+5)-1=0
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let u=3x%2B5
8u%5E2%2B2u-1=0
%284u-1%29%282u%2B1%29=0
Two solutions:
4u-1=0
4u=1
u=1%2F4
3x%2B5=1%2F4
12x%2B20=1
12x=19
highlight%28x=19%2F12%29
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.
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2u%2B1=0
2u=-1
u=-1%2F2
3x%2B5=-1%2F2
6x%2B10=-1
6x=11
highlight%28x=11%2F6%29
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.