Tolong yang dijawab dengan cara yang lengkap, no 2,3,dan4 ya. Thank you

2. a. (-3m+4n-6) + (7n-8m+10) = -3m + 4n - 6 + 7n - 8m + 10
                                                  = -3m - 8m + 4n + 7n - 6 + 10
                                                  = -11m + 11n + 4
b. (15a+7b-5c) + (-11a-12b+13d) = 15a + 7b - 5c - 11a -12b +13d
                                                      = 15a - 11a + 7b - 12b - 5c + 13d
                                                      = 4a - 5b - 5c + 13d

3.a. (-3m+4n-6) - (7n-8m+10) = -3m + 4n - 6 - 7n + 8m - 10
                                                = -3m + 8m + 4n - 7n - 6 - 10
                                                = 5m - 3n - 16
b. (15a+7b-5c) - (-11a-12b+13d) = 15a + 7b - 5c + 11a + 12b - 13d
                                                     = 15a + 11a +7b + 12b - 5c - 13d
                                                     = 26a + 19b - 5c - 13d

4. 5x-6y+8z+(7x-9y)-(2y+9z-10) = 5x - 6y + 8z + 7x - 9y - 2y - 9z + 10
                                                    = 5x + 7x - 6y - 9y - 2y + 8z - 9z +10
                                                    = 12x - 17y - z + 10