Question

Factor the polynomial 64x^3-125

Answer 1

$64 x^{3} -125$

= $(4x)^{3} - 5^{3}$ ------> because, $(4x)^{3}$ is same as 64x³ and 
                                                $5^{3}$ is same as 125

Using the formula: $a^{3}- b^{3} =(a-b)(a ^{2} +ab+b ^{2} )$, we get, 

= $(4x -5)((4x)^{2} +4x*5+ 5^{2} )$

= $(4x -5)(16 x^{2} +20x+25)$   ------>that's your answer!!