4. (9x^2 + 13x) + (4x^2 - 8x)
(9x^2 + 13x)
9x^2 = 81 x + 13 x = 94x
(4x^2 - 8x)
4x^2 = 16x - 8x = 8x
94x + 8x = 102x
The answer is 102x
5. (x^2 + 4x + 6) + (x^2 + 8x + 3)
(x^2 + 4x + 6)
4x + 6 = 10x
10x + x^2 = 10x^2
(x^2 + 8x + 3)
8x + 3 = 11x
x^2 + 11x = 11x^2
The answer i 11x^2
6. (-3x^2 + 2x - 8) + (x^2 + 4x)
(-3^2 + 2x + 8)
-3^2 = 9
2x + 8 = 10x
10x + 9 = 19x
(x^2 + 4x)
x^2 + 4x = 4x^2
19x + 4x^2 = 23x^2
The answer is 23x^2.
