Question

( x^{3}-frac{1}{y^{3}}-frac{3 x}{y}left(x-frac{1}{y}right) )
( =left(x-frac{1}{y}right)^{3}(2)+40 )
Quenchm
( left(a^{2}-bright)^{3}=a^{3}-b^{3}-3 a b(a-b) )

# 36. *** **is equal to (1) (x+y)3 (2) (+-+ (3) (x = 1) (4) (x+4)

Solution