1.
a, x + (-30) - [95 + (-40) + (-30)]
= x + (-60) = x - 60
b, a + (273 - 120) - (270 - 120)
= a + 3
c, b - (294 + 130) + (94 + 130)
= b - 648
PHẦN 2. MIK KO BT LM
1.
a) x+(-30)-[95+(-40)+(-30)]
= x- 30-25
= x -55
b)a+(273-120)-(270-120)
= a+273-120-270+120
= a+3
c) b-(294+130)+(94+130)
= b-294-130+94+130
=b-200
2.
a) -a-(b-a-c)
= -a-b+a+c
= -b+c
b)-(a-c)-(a-b+c)
= -a+c-a+b-c
= -2a+b
c) -(a-b+c)-(a+b+c)
= -a+b-c-a-b-c
= -2a-2c