Question

разложите на множители!
x^3+27y^3+x^2+6xy+9y^2

Answer 1

$x^3+27y^3+x^2+6xy+9y^2=\\=(x+3y)(x^2-3xy+9y^2)+(x+3y)^2=\\=(x+3y)(x^2-3xy+9y^2+x+3y)\\\\\boxed {a^3+b^3=(a+b)(a^2-ab+b^2);\;a^2+2ab+b^2=(a+b)^2}$