1) 15 = 5(x + 2)
15 = 5x + 10
15 - 10 = 5x + 10 - 10
5 = 5x
5/5 = 5x/5
1 = x
2) 5n + 34 = -21(1-7n)
5n + 34 = -21 + 147n
5n + 34 = -21 + 147n
5n - 147n + 34 = -21 + 147n - 147n
-142n + 34 = -21
-142n + 34 - 34 = -21 - 34
-142n = -55
-142n/-142 = -55/-142
n = 55/142