3 + c = 15
subtract 3 from both-side of the equation
3 - 3 + c = 15 -3
c= 12
7 = m+ 11
subtract 11 from both-side of the equation
7 - 11 = m+11 - 11
-4 = m
m=-4
c-24=10
add 24 to both-side of the equation
c - 24+ 24= 10 + 24
c= 34
16 = g- 5
add 5 to both-side of the equation
16+5 = g - 5 + 5
21 = g
g= 21
2n = 84
divide both-side of the equation by 2
2n/2 = 84/2
n =42
-5r = 20
dvide both-side of the equation by -5
-5r/-5 = 20/-5
r = -4
c/4 = 16
multiply both-side of the equation by 4
c = 16(4)
c= 64

multiply both-side of the equation by 3/2

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a= 18