6X^12-18X^9+18^8-54X^5-36X^3+108

Answer 1

you always want to start by putting like terms together. So why don't you do that first and then its really easy from there all you have to do is follow the signs(- or +) and add or subtract

Answer 2

so would it be
6X^12+18^8+108-18X^9-54X^5-36X^3