Rút gọn:

rút gọn:
1)a+|a|
2)a-|a|
3)a.|a|
5)3.(x-1)+2.|x+3|
7)|x+3|+|x+5|
8)|x-1|+|x-3|
9)|4x+3|-|x-2|
10)|x+1|+|x+3|+|x-2|-|x+5|