(3x2 + 6x - 1) + (4x2 + 5x + 9)

7 x^2 + 11 x + 8

Step-by-step explanation:

Simplify the following:

4 x^2 + 3 x^2 + 6 x + 5 x - 1 + 9

Grouping like terms, 4 x^2 + 3 x^2 + 6 x + 5 x - 1 + 9 = (3 x^2 + 4 x^2) + (6 x + 5 x) + (-1 + 9):

(3 x^2 + 4 x^2) + (6 x + 5 x) + (-1 + 9)

3 x^2 + 4 x^2 = 7 x^2:

7 x^2 + (6 x + 5 x) + (-1 + 9)

6 x + 5 x = 11 x:

7 x^2 + 11 x + (-1 + 9)

9 - 1 = 8:

7 x^2 + 11 x + 8