Simplify (-6x^4-5x^3+x^2)+(4x^2+6x^4-4x^3)

$(- 6 x^{4} - 5 x^{3} + x^{2}) + (4 x^{2} + 6 x^{4} - 4 x^{3})$

Remove parentheses.

$- 6 x^{4} - 5 x^{3} + x^{2} + 4 x^{2} + 6 x^{4} - 4 x^{3}$

Combine the opposite terms in $- 6 x^{4} - 5 x^{3} + x^{2} + 4 x^{2} + 6 x^{4} - 4 x^{3}$ .

Add $- 6 x^{4}$ and $6 x^{4}$ .

$- 5 x^{3} + x^{2} + 4 x^{2} + 0 - 4 x^{3}$

Add $- 5 x^{3} + x^{2} + 4 x^{2}$ and $0$ .

$- 5 x^{3} + x^{2} + 4 x^{2} - 4 x^{3}$

Subtract $4 x^{3}$ from $- 5 x^{3}$ .

$- 9 x^{3} + x^{2} + 4 x^{2}$

Add $x^{2}$ and $4 x^{2}$ .

$- 9 x^{3} + 5 x^{2}$