always do thesame to both sides
with one placeholder, try to get the placeholder by itself on one side
one tactic is to isolate the placeholder
1)
5r-5=55
factor
5(r-1)=5(11)
divide both sides by 5
r-1=11
add 1 to both sides
r=12
2)
9m-16=65
add 16 to both sides
9m=81
divide both sides by 9
m=9
3)
6p-8=22
add 8 to both sides
6p=30
divide both sides by 6
p=5
4)
z/11-2=7
get rid of fraction
multiply both sides by 11
1(z/11-2)=77
z-22=77
add 22 to both sides
z=99
5)
9r-4=50
add 4 to both sides
9r=54
divde both sides by 9
r=6
6)
4z-21=11
add 21 to both sides
4z=32
divide both sides by 4
z=8
7)
d/10+12=29
get rid of fraction
multiply both sides by 10
10(d/10+12)=290
d+120=290
subtract 120 from both sides
d=170
8)
2s-8=22
add 8 to both sides
2s=30
divide both sides by 2
s=15
