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

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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)   (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:
-------
y = kx^3
---
250 = k*5^3 = 125k
k = 2
--------------------
y = 2x^3
a) y when x=8
b) x when y= 128

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