Answer
12$x^{2}$ + 15x - 9
Work Step by Step
(4$x^{2}$ + 6x - 7) + (8$x^{2}$+9x-2)
The like terms are 4$x^{2}$ and 8$x^{2}$ containing the same variable to the same power($x^{2}$), as well as 6x and 9x (both containing x), and the constant terms -7 and -2.
We begin by grouping these pairs of like terms.
(4$x^{2}$ + 8$x^{2}$) + (6x + 9x) +(-7-2)
= 12$x^{2}$ + 15x - 9
