(4x+3y)cube ?

(4x + 3y)^3
= (4x + 3y)(4x + 3y)^2
= (4x + 3y)(16x^2 + 24xy + 9y^2)
= 64x^3 + 96x^2y + 36xy^2 + 48x^2y + 72xy^2 + 27y^3
= 64x^3 + 144x^2y + 108xy^2 + 27y^3

(4x + 3y)^3
= (4x + 3y)(4x + 3y)(4x + 3y)
= (4x*4x + 3y*4x + 4x*3y + 3y*3y)(4x + 3y)
= (16x^2 + 12xy + 12xy + 9y^2)(4x + 3y)
= (16x^2 + 24xy + 9y^2)(4x + 3y)
= 16x^2*4x + 24xy*4x + 9y^2*4x + 16x^2*3y + 24xy*3y + 9y^2*3y
= 64x^3 + 96x^2y + 36xy^2 + 48x^2y + 72xy^2 + 27y^3
= 64x^3 + 96x^2y + 48x^2y + 36xy^2 + 72xy^2 + 27y^3
= 64x^3 + 144x^2y + 108xy^2 + 27y^3

(4x + 3y)(16x² + 24xy + 9y²)

64x³ + 96x²y + 36xy²
_____48x²y + 72xy² + 27y³

64x³ + 144x²y + 108xy² + 27y³

you want to do binomial theorem

(4x)^3+ ((3C1 4^2)(x)^2 x(3y)) +((3C2 4)(x) x(3y)^2)+(3y)^3
C=Ncr