Question 141587
Find an equation of variation where y varies jointly as x and z and inversely as the square of w and y=20 when x=-0.5, z=4, and w=5.

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y kxz/w^2
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Find "k":
20 = k*-0.5*4/5^2
20 = -2k/25
400 = -2k
k = -200
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EQUATION:
y = -200xz/w^2
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Cheers,
Stan H.