Question

what is the method to this 2nd problem

Answer 1

let a=2x
b=3y
c=4z

a³+b³+c³-3abc = (a+b+c)(a²+b²+c²-ab-bc-ca)

(2x)³+(3y)³+(4z)³-3[(2x)(3y)(4z)] = (2x+3y+4z)[(2x)²+(3y)²+(4z)²-(2x)(3y)-(3x)(4z)-(4z)(2x)]

8x³+27y³+64z³-72xyz = 0[(2x)²+(3y)²+(4z)²-(2x)(3y)-(3x)(4z)-(4z)(2x)] [{(2x+3y+4z = 0)}]

8x³+27y³+64z³-72xyz = 0(PROVED)

HOPE THIS WILL HELP YOU!!!!