Respuesta :

3r - 8 = 7 + 8r (make rs on 1 side, numbers on other)
5r = -15(divide by 5 now)
r = -3 (<---Answer)
Hope this helped!
r = -3, So the answer would be B)

-8 = 7 + 8r - 3r
-8 = 7 + 5r
-8 - 7 = 5r
-15 = 5r
-15/5 = r
-3 = r
r = -3.

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