(2x^2 + 4x + 6) - (-3x - 5x^2 + 4)
The negative sign separating the expressions is just multiplying the rightmost expression by -1.
(2x^2 + 4x + 6) + (3x + 5x^2 - 4)
Now, let's add together terms that share the same variable.
2x^2 + 5x^2 = 7x^2
4x + 3x = 7x
6 + (-4) = 2
Let's combine each of these terms into one expression.
7x^2 + 7x + 2 is the final answer.