I'm assuming the the numbers coming after the variables are meant to be exponents, and if I'm wrong just let me know
-3x^4 - 2x^3 + 3x^2 + 3x^4 - 4x^3 + x^2, rearrange to have like terms in order
-3x^4 +3x^4 - 2x^3 - 4x^3 +3x^2 + x^2, now simplify
0 -6x^3 + 4x^2
