I have this problem. I have figured most of it out, but I am not sure what the last part is asking or know how to find it.
View attachment 5035
I have:
x^2y=132
y=132/x^2
A=x^2+4xy
A=x^2+528/x
A'=2x-528/x^2
2x-528/x^2=0 x=6.42
I have got this far. Any tips on the last piece? What do they even want?