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

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

Remove parentheses.

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

Add $3 x^{2}$ and $4 x^{2}$ .

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

Subtract $3 x$ from $2 x$ .

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

Add $- 5$ and $7$ .

$7 x^{2} - x + 2$