Simplify (9x^4-3x^3+4x^2+5x+7)+(11x^4-4x^2-11x-9)

$(9 x^{4} - 3 x^{3} + 4 x^{2} + 5 x + 7) + (11 x^{4} - 4 x^{2} - 11 x - 9)$

Remove parentheses.

$9 x^{4} - 3 x^{3} + 4 x^{2} + 5 x + 7 + 11 x^{4} - 4 x^{2} - 11 x - 9$

Combine the opposite terms in $9 x^{4} - 3 x^{3} + 4 x^{2} + 5 x + 7 + 11 x^{4} - 4 x^{2} - 11 x - 9$ .

Subtract $4 x^{2}$ from $4 x^{2}$ .

$9 x^{4} - 3 x^{3} + 5 x + 7 + 11 x^{4} + 0 - 11 x - 9$

Add $9 x^{4} - 3 x^{3} + 5 x + 7 + 11 x^{4}$ and $0$ .

$9 x^{4} - 3 x^{3} + 5 x + 7 + 11 x^{4} - 11 x - 9$

Add $9 x^{4}$ and $11 x^{4}$ .

$20 x^{4} - 3 x^{3} + 5 x + 7 - 11 x - 9$

Subtract $11 x$ from $5 x$ .

$20 x^{4} - 3 x^{3} - 6 x + 7 - 9$

Subtract $9$ from $7$ .

$20 x^{4} - 3 x^{3} - 6 x - 2$