3+(-2)+x=5
1 +x= 5
x= 5-1
x=4
Vậy x=4
= 17-[12-(-20)]
=17-32
= -15
16:XVI
49:XLIX
154:CILV
1874:MDCCCLXXXIV
=17-[12-(-20)]
=17- 32
= -15