Simplify (4x^2-9x+3)+(-2x^2-5x-6)

$(4 x^{2} - 9 x + 3) + (- 2 x^{2} - 5 x - 6)$

Remove parentheses.

$4 x^{2} - 9 x + 3 - 2 x^{2} - 5 x - 6$

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

$2 x^{2} - 9 x + 3 - 5 x - 6$

Subtract $5 x$ from $- 9 x$ .

$2 x^{2} - 14 x + 3 - 6$

Subtract $6$ from $3$ .

$2 x^{2} - 14 x - 3$