Question

(5x +2y+)(25x² -10xy +4y² )

Answer 1

let a=5x and b=2y
this is in the form a³+b³=(a+b)(a²-ab+b²)
=(5x+2y)((5x)²-(5x)(2y)+(2y)²)
=(5x)³+(2y)³
=125x³+8y³

Answer 2

We know that

$(a+b)(a^2-ab+b^2) = a^3+b^3$

$(5x+2y)(25x^2-10xy+4y^2) = 125x^3+8y^3$