6) 4r + 8 + 5 = -15 - 3r
4r + 3r = -15 -8 - 5
7r = -28
r = -28/7
r = -4
8) 3n - 15 = 7n + n
-15 = 7n + n - 3n
-15 = 5n
n = -15/5
n = -3
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