Answer:
x=31, y=23, z=34
Step-by-step explanation:
The first shelf is x. The second shelf is y. The third shelf is z.
x+y=54.
y+z=57
x+y+z=88
You can substitute 54 in for x+y in the third equation to solve for z.
54+z=88
Subtract 54
z=34
Now that you know z, substitute it in in the second equation.
y+34=57
y=23
Finally, substitute the known y value into the first equation.
x+23=54
x=31
