Hi, I've got 3 problems that I'm really stuck on, but I'll post the first one.

Any help MUCH appreciated because the assignment is due in about 14 hours.

1. Maximize P=xyz with x+z=12, y+z=12, and x,y,and z >=0

The farthest I got on this one was to rearrange the variables to make z the only unknown, then taking the derivative, but I'm stuck from there.

the last part I have written on it is 16z+z^2 = 48