Simplify (7x^2+3x+6)+(-4x^2+5x-6)

$(7 x^{2} + 3 x + 6) + (- 4 x^{2} + 5 x - 6)$

Remove parentheses.

$7 x^{2} + 3 x + 6 - 4 x^{2} + 5 x - 6$

Combine the opposite terms in $7 x^{2} + 3 x + 6 - 4 x^{2} + 5 x - 6$ .

Subtract $6$ from $6$ .

$7 x^{2} + 3 x - 4 x^{2} + 5 x + 0$

Add $7 x^{2} + 3 x - 4 x^{2} + 5 x$ and $0$ .

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

Subtract $4 x^{2}$ from $7 x^{2}$ .

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

Add $3 x$ and $5 x$ .

$3 x^{2} + 8 x$