SOLUTION: The variable z varies jointly with x and y. Also, z=-75 when x =3 and y=-5. Write an equation that relates x, y and z. Then find z when x=2 and y=6

Algebra ->  Equations -> SOLUTION: The variable z varies jointly with x and y. Also, z=-75 when x =3 and y=-5. Write an equation that relates x, y and z. Then find z when x=2 and y=6      Log On


   

Question 1071758: The variable z varies jointly with x and y. Also, z=-75 when x =3 and y=-5. Write an equation that relates x, y and z. Then find z when x=2 and y=6
Answer by stanbon(75887) About Me  (Show Source):
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The variable z varies jointly with x and y. Also, z=-75 when x =3 and y=-5. Write an equation that relates x, y and z. Then find z when x=2 and y=6
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z = k*x*y
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Solve for "k" using
-75 = k*3*(-5)
k = 5
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Equation::
z = 5*x*y
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Find z when x = 2 and y = 6
z = 5*2*6
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Ans:: z = 60
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Cheers,
Stan H.
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