Question

how do i factorise 6x+9x cubed?

Answer 1

if your is (6x+9x)³ then answer is

factorise (6x+9x)³

= (15x)³ = 3375x³

if your question is (6x+9)³ then answer is

(6x+9)³ = (6x)³+9³+3(6x)²×9+3(6x)×9²

= 216x³+721 +3×36×9x²+3×6×81x

= 216x³+721+972x²+1458x

= 216x³+972x²+1458x +721