Answer:
3x^6+3x^3-18
Step-by-step explanation:
Use the Foil method: (a+b)(c+d)=ac+ad+bc+bd
1. 3x^6+9x^3-6x^3-18
2. Collect like terms 3x^6+(9x^3-6x^3)-18
3. Simplify and that should give you 3x^6+3x^3-18 Hope that helps !