Answer:
Step-by-step explanation:
16. 9a=15x12
9a=180
a=20
17. 9-t=t+3
-t-t=3-9
-2t=-6
t=6/2
t=3
18. 2y+12=3y+12-y
2y+y-3y=12-12
0=0
=> 2y= -12
y= -6
19.
17+3z-6-11z=-7z-14
17+3z-6-11z+14=-7z
17-6+14=-7z-3z+11z
25= -10Z+11z
25=Z
