To solve for a variable, isolate it! Get the variable alone on one side of the equation.
13) -15 = -4m + 5 ... -20 = -4m ... m = 5
14) 10 - 6v = -104 ... -6v = -114 ... v = 19
15) 8n + 7 = 31 ... 8n = 24 ... n = 3
16) -9x - 13 = -103 ... -9x = -93 ... x = 31/3
17) (n + 5) / -16 = -1 ... n + 5 = 16 ... n = 11
18) -10 = -10 + 7m ... 0 = 7m ... m = 0
19) -10 = -10(k - 9) ... 1 = k - 9 ... k = 10
20) (m / 9) - 1 = -2 ... m / 9 = -1 ... m = -9
21) 9 + 9n = 9 ... 9n = 0 ... n = 0
22) 7(9 + k) = 84 ... 9 + k = 12 ... k = 3
I cannot clearly read 23 and 24, but I hope you can see the principles I applied to produce these answers.
