1.the street is busy.

2.the city is big.

3.I live in the countryside.

4. my hometown is a big town

5 what is your hometown like?

Ta có: A+B = (a+b-5)+(-b-c+1)=a+b-5-b-c+1=a-c-4

C-D = (b-c-4)-(b-a)=b-c-4-b+a=a-c-4

=> A+B=C-D  (đpcm).

wao