SOLUTION: The variable z varies directly with x and inversely with the cube of y. a) Write the formula for this variation. b) If z=12/27 when x=6 and y=3 find z when x=5 and y=4.

Algebra ->  Rational-functions -> SOLUTION: The variable z varies directly with x and inversely with the cube of y. a) Write the formula for this variation. b) If z=12/27 when x=6 and y=3 find z when x=5 and y=4.      Log On


   

Question 858165: The variable z varies directly with x and inversely with the cube of y.
a) Write the formula for this variation.
b) If z=12/27 when x=6 and y=3 find z when x=5 and y=4.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The variable z varies directly with x and inversely with the cube of y.
a) Write the formula for this variation.
z = k*x/y^3
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b) If z=12/27 when x=6 and y=3
Find "k"::
12/27 = k*6/3^3
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12 = 6k
k = 2
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Equation:
y = 2x/y^3
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find z when x=5 and y=4.
z = 2*5/4^3
z = 10/64
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Cheers,
Stan H.
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