SOLUTION: Hi, I am trying to review for a final and am stuck on this one. Use method of substitution to solve system: x-y^3=1 2x=9y^2+2 This is what I have done: x=1+y^3 2(1+y^3)=

Algebra ->  Systems-of-equations -> SOLUTION: Hi, I am trying to review for a final and am stuck on this one. Use method of substitution to solve system: x-y^3=1 2x=9y^2+2 This is what I have done: x=1+y^3 2(1+y^3)=       Log On


   

Question 118184This question is from textbook Fund of Trig and Alg
: Hi, I am trying to review for a final and am stuck on this one.
Use method of substitution to solve system:
x-y^3=1
2x=9y^2+2
This is what I have done:
x=1+y^3
2(1+y^3)= 9y^2+2
2+2y^3=9y^2+2
2y^3=9y^2+2
2y^3-9y^2=0
y(y+3)(y-3) This question is from textbook Fund of Trig and Alg

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Use method of substitution to solve system:
x-y^3=1
2x=9y^2+2
This is what I have done:
x=1+y^3
2(1+y^3)= 9y^2+2
2+2y^3 = 9y^2+2
2y^3=9y^2
2y^3-9y^2=0
y^2(2y-9) = 0
y = 0 or y = 9/2
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Now solve for "x":
If y = 0, x = 0^3+1 = 1
If y = (9/2), x = (9/2)^3+1 = 729/8+1 = 737/8= 91 1/8
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Cheers,
Stan H.