Simplify (x^4+3x^3-x^2+6)+(2x^4-3x+9)

$(x^{4} + 3 x^{3} - x^{2} + 6) + (2 x^{4} - 3 x + 9)$

Step 1

Remove parentheses.

$x^{4} + 3 x^{3} - x^{2} + 6 + 2 x^{4} - 3 x + 9$

Step 2

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

$3 x^{4} + 3 x^{3} - x^{2} + 6 - 3 x + 9$

Step 3

Add $6$ and $9$ .

$3 x^{4} + 3 x^{3} - x^{2} - 3 x + 15$