We want to know the value of r so
2r + 2 = 10
is satisfied
2r + 2 - 2 = 10 -2 [Substracting 2 both sides]
2r + 0 = 8 [2-2=0 and 10-2=8]
2r = 8
2r/2 = 8/2 [Dividing by 2 both sides]
r = 4
