Question 31123
{{{4x-5)^3}}} is a perfect cube
using the formula for perfect cubes:
perfect cube (2 forms): A³ ± 3A²B + 3AB² ± B³ = (A ± B)³
we get: {{{(4x)^3 - 3(4x)^2(5) + 3(4x)(5)^5 - 5^3}}}
{{{64x^3 - 3(16x^2)(5) + 3(4x)(5^2) - 5^3}}} 
= {{{64x^3 - 240x^2 + 300x - 125}}}

regards,
Brian bird