Answer:
Step-by-step explanation:
We assume your equations are intended to be ...
[tex]C(x,y)=x^2-2xy+9y^2+3x-87y-6\\R(x,y)=5x+7y[/tex]
Then the profit equation is ...
[tex]P(x,y)=R(x,y)-C(x,y)=5x+7y-x^2+2xy-9y^2-3x+87y+6\\=-x^2+2xy-9y^2+2x+94y+6[/tex]
The partial derivatives of profit with respect to x and y are zero when profit is maximized.
∂P/∂x = 0 = -2x +2y +2
∂P/∂y = 0 = 2x -18y +94
Simplifying, these equations are ...
Substituting the first into the second gives ...
x -9(x -1) = -47
-8x = -56
x = 7
y = 7 -1 = 6
The company will maximize profit by selling 7000 panels of type A and 6000 panels of type B.