Question

quiero resolver (x-3y )³

Answer 1

x al cubo menos 27y al cubo

Answer 2

(x-3y)³  usando la formula 
(a -b) ³ = a³ - 3(a²)(b) +3(a)(b²) - b³
entonces 
x³ - 3(x)²(3y)+ 3(x)(3y)² -(3y)³
x³ - 9x²y + 3x(9y²) - 27y³
x³ -9x²y +27xy² -27y³