1. D, 9m - 5m equals 4m and 6+(-6) equals 0. When a + and a - are by each other it is a negative.
2. B, 3r^2 + 4r^2 equals 7r^2. 7r - 8r equals -r. 1 - 2 equals -1.
3. D, 6h - 9h equals -3h. 1 + 4 equals 5.
4. D, -m + m equals 0. -4 + -5 equals -9.
5. C, 4x + 3x equals 7x. 4 + 2 + 1 equals 7