Bài 1
a. x+(−30)−[95+(−40)+(−30)x+(−30)−[95+(−40)+(−30)
=x−30−(95−40−30)=x−30−(95−40−30)
=x−30−95+40+30=x−30−95+40+30
=x−(30−30)−95+40=x−(30−30)−95+40
=x−55=x−55
b. a+(273−120)−(270−120)a+(273−120)−(270−120)
=a+273−120−270+120=a+273−120−270+120
=a+(273−270)−(120−120)=a+(273−270)−(120−120)
=a+3−0=a+3−0
=a+3=a+3
c. −(294+130)+(94+130)−(294+130)+(94+130)
=−294−130+94+130=−294−130+94+130
=(−294+94)−(130−130)=(−294+94)−(130−130)
=−200
Bài 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. b- ( b+a - c)
= b- b -a +c
= -a +c
d. -(a-b+c)- (a+b+c)
= -a + b - c -a -b- c
= -2a -2b
