Alg1.1.12

From Exampleproblems

Evaluate $(2x+3y)(4x^2-6xy+9y^2)\,$

Rearrange the variables in the second factor,which looks like, $(2x+3y)((2x)^2-(2x)(3y)+(3y)^2)\,$

This can be interpreted as in the formula, $(a + b)(a 2 - a b + b 2) = a 3 + b 3$ Hence the solution of the expression is $(2x)^3+(3y)^3\,$

Final solution is $8x^3+27y^3\,$