Combine like terms that share a common variable. If a scalar multiple is outside the parentheses, use the distributive property to expand the expression.
15) I cannot read the whole expression.
16) 4n - n = 3n
17) -3x - 9 + 15x = 12x - 9
18) -9k + 8k = -k
19) -16n - 14n = -30n
20) 15n - 19n = -4n
21) - 4 + 7(1 - 3m) = -4 + 7 - 21m = -21m + 3
22) -5n + 3(6 + 7n) = -5n + 18 + 21n = 16n + 18
23) -2n - (9 - 10n) = -2n - 9 +10n = 8n - 9
24) 10 - 5(9n - 9) = 10 - 45n + 45 = -45n + 55
25) 9a + 10(6a - 1) = 9a + 60a - 10 = 69a - 10
26) -9(6m - 3) + 6(1 + 4m) = -54m + 27 + 6 + 24m = -30m + 33
27) -10(1 - 9x) + 6(x - 10) = -10 + 90x + 6x - 60 = 96x - 70
28) 5(-2n + 4) + 2(n + 3) = -10n + 20 + 2n + 6 = -8n + 26