Factorise 27x3+y3+z3−9xyz [2 MARKS]
Formula: 1 Mark
Substitution & Simplication: 1 Mark
x3+y3+z3−3xyz
=(x+y+z)(x2+y2+z2−xy−yz−zx)
Comparing from above identity
=(3x)3+y3+z3−3(3x)yz
=(3x+y+z)((3x)2+y2+z2−3xy−yz−3zx)
=(3x+y+z)(9x2+y2+z2−3xy−yz−3zx)