Posted by ferrer on .
combine like terms
18x^4+2x^3y^312y^317x^4=

math 
PsyDAG,
18x^4+2x^3(y^3)12y^317x^4=
x^4 + 2x^3 (y^3)  2y^3  1 =
x^4 + 2x^3 (y^3)  2y^3  1 =
x^4 + 2y^3 (x^3  1)  1
This should be it, unless the parentheses are differently arranged.
I hope this helps. Thanks for asking.