SOLUTION: Please help find the values of A and B: A-B=1 and 2A^2+20=B^3

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Question 1063061: Please help find the values of A and B:
A-B=1 and 2A^2+20=B^3
Found 2 solutions by Fombitz, rothauserc:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
A=1%2BB
So,
A%5E2=%281%2BB%29%5E2
A%5E2=1%2B2B%2BB%5E2
and
2%281%2B2B%2BB%5E2%29%2B20=B%5E3
B%5E3-2B%5E2-4B-22=0
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Graph the B function to find where it has a zero.
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B=4.2
so then,
A-4.2=1
A=5.2

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
A - B = 1
:
1) A = B + 1
:
2) 2A^2 + 20 = B^3
:
substitute for A in equation 2 using equation 1
:
2(B+1)^2 + 20 = B^3
:
2(B^2+2B+1) + 20 = B^3
:
2B^2 +4B +2 + 20 = B^3
:
B^3 -2B^2 -4B -22 = 0
:
a graph of this equation will help
:
+graph%28+300%2C+200%2C+-0.3%2C+5.2%2C+-35%2C+40%2C+x%5E3-2x%5E2-4x-22%29+
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B is approximately 4.2
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A is 5.2 and B is 4.2
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