Answer:
9. -16
10. 3
11. 4
Step-by-step explanation:
9. 21 = 5 - r
Subtract 5 from both sides;
16 = -r
Divide both sides by -1
-16 = r OR r = -16
10. 8 - 5b = -7
Subtract 8 from both sides;
-5b = -15
Divide both sides by -5
b = 3
11. -10 = 6 - 4m
Subtract 6 from both sides;
-16 = -4m
Divide both sides by -4
4 = m OR m = 4
