Question: The Difference of one number and four times a second number is 32. Find the minimum Product.

How far I got: P = x * Y // x-4y=32 solve for one variable in (x-4y=32), then input the found variable into p = x * y.

32+4y = x = P = (32+4y)y = P= 32y+4y^2

then get the derivative of P, dp/dx= 32+8y ?

I'm not sure if I'm doing it right or not, can i get some guidance! Thanks

Question

Question: The Difference of one number and four times a second number is 32. Find the minimum Product.  

   How far I got:  P = x * Y   // x-4y=32   solve for one variable in (x-4y=32), then input the found variable into p = x * y. 

 32+4y = x  =>   P = (32+4y)y = > P= 32y+4y^2 

then get the derivative of P, dp/dx= 32+8y ? 

 I'm not sure if I'm doing it right or not, can i get some guidance! Thanks

anonymous · Answer

$$x-4y=32$$
$$P=xy$$
$$x=32+4y$$
$$P(y)=(32+4y)y=32y+4y^2$$

anonymous · Answer

looks good

anonymous · Answer

$$P'(y)=32+8y$$
set equal to zero and get $y=-4$

anonymous · Answer

Thank you man!