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

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

Simplify the expression.

Remove parentheses.

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

Subtract $9$ from $4$ .

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

Add $- x$ and $3 x$ .

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

Add $3 x^{3}$ and $5 x^{3}$ .

$7 x^{4} + 8 x^{3} + 2 x - 5$