1. solution: build a grain depot to store x tons of grain. Countable equation, get:

2(x- 12)=x

(2x-24)=x

2x-24=x

2x-x=24

x=24

2. Solution: Suppose X tons are shipped on the first day. Countable equation, get:

2.5x+x= 140

3.5x= 140

x=40

3. In the 1 th equation, x is a number.

In the second formula, x is the number B.

In the third formula, x is a number.

accord with