SOLUTION: Please help me solve y^3 - 7y^3/2 -8= 0

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Question 325540: Please help me solve y^3 - 7y^3/2 -8= 0
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Use a substitution,
Let u=y%5E3%2F2, then u%5E2=y%5E3
y%5E3+-+7y%5E3%2F2+-8=+0
u%5E2+-+7u+-8=+0
%28u%2B1%29%28u-8%29=0
Two solutions:
u=-1
y%5E%283%2F2%29=-1
No solution.
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u-8=0
u=8
y%5E%283%2F2%29=8
y=8%5E%282%2F3%29
y=4