SOLUTION: I do not understand inverse and direct variation. How would i set this up? suppose z varies directly as x and inversly as the square of y. If x=5 and y=2, then z=40. find z when

Algebra ->  Proportions  -> Lessons -> SOLUTION: I do not understand inverse and direct variation. How would i set this up? suppose z varies directly as x and inversly as the square of y. If x=5 and y=2, then z=40. find z when       Log On


   

Question 755407: I do not understand inverse and direct variation.
How would i set this up?
suppose z varies directly as x and inversly as the square of y. If x=5 and y=2, then z=40. find z when x=6 and y=4
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
suppose z varies directly as x and inversly as the square of y.
z = k*x/y^2
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Solve for "k" using "If x=5 and y=2, then z=40".
40 = k*5/(2^2)
160 = 5k
k = 160/5
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Equation:
z = (160/5)x/y^2
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find z when x=6 and y=4
z = (160/5)*6/16
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z = 10*6/5
z = 12
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Cheers,
Stan H.
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