Question

How many liters of water can the three containers hold in all? Container 1: (x-1) Container 2: x Container 3: (x+1)

Answer 1

We know that:

Container 1: can hold $(x-1)$
Container 2:  can hold $(x)$
Container 3:  can hold  $(x+1)$

In total there are $3x's$

$-1+1 = 0$

Therefore, the correct answer is 3x.