SOLUTION: Given that y varies directly with the cube of x, and y=250 when x=5, find: a) y when x=8 b) x when y= 128

Algebra ->  Rational-functions -> SOLUTION: Given that y varies directly with the cube of x, and y=250 when x=5, find: a) y when x=8 b) x when y= 128      Log On


   

Question 1174227: Given that y varies directly with the cube of x, and y=250 when x=5, find:
a) y when x=8
b) x when y= 128
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Given that y varies directly with the cube of x, and y=250 when x=5, find:
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y = kx^3
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250 = k*5^3 = 125k
k = 2
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y = 2x^3
a) y when x=8
b) x when y= 128