a. 5x=15
x=3
b. z+10=13
z=13-10
z=3
c. 7y+1=22
7y=22-1
y=3
d. 6u=3u+18
6u-3u=18
3u=18
u=3
e.
9x+1=7x+19
9x-7x=19-1
2x=18
x=9
f. 7y+5=2y+30
7y-2y=30-5
5y=25
y=5
g. 9t+6= t +30
9t-t=30-6
8t=24
t=3
h. 5x+6 = x+38
5x-x=38-6
4x=32
x=8
i. 3y+14=y+20
3y-y=20-14
2y=6
y=3