SOLUTION: I need some help with this please. write a formula that expresses the relationship P varies jointly as x and y and P=8 when x=3 and y=-10

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Question 528567: I need some help with this please.
write a formula that expresses the relationship P varies jointly as x and y and P=8 when x=3 and y=-10
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
write a formula that expresses the relationship P varies jointly as x and y
:
Let k = the the constant of variation
P = xyk
:
and P=8 when x=3 and y=-10
8 = 3*-10*k
find k
8 = -30k
k = 8%2F%28-30%29
k = -.267
:
P = -.267xy is the formula