Answer: The complete factored form of the given expression is [tex](4x+3y)(16x^2-12xy+9y^2).[/tex]
Step-by-step explanation: We are given to factor the following cubic expression completely :
[tex]E=64x^3+27y^3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)[/tex]
We will be using the following formula :
[tex]a^3+b^3=(a+b)(a^2-ab+b^2).[/tex]
We have, from expression (i) that
[tex]E\\\\=64x^3+27y^3\\\\=(4x)^3+(3y)^3\\\\=(4x+3y)((4x)^2-4x\times3y+(3y)^2)\\\\=(4x+3y)(16x^2-12xy+9y^2).[/tex]
Thus, the complete factored form of the given expression is [tex](4x+3y)(16x^2-12xy+9y^2).[/tex]