Question

bai 1,  thuc hien phep tru

a, (a-1)-(a-3)

b, (2+b)-(b+1)

c, -(1-2)+(5-c)

d, -(a-c)-(a-b+c)

bai 2, tim x, biet

a, -x+8= -17

b, 35-x=37

c, -19-x= -20

d, 2130-(x+130)+72= -64

      giup minh voi, minh can gap, cam on cac ban nhieu

Answer 1

bài 1 :

a, (a-1 ) - (a-3) = a-1 -a+3= 2

b, (2+b) -( b +1) = 2+b - b - 1= 1

c, -(1-2) + ( 5 -c) =  6 -c 

d, - ( a-c) - ( a-b +c) = b

Answer 2

a, (a-1)-(a-3)

=a-1-a+3

=2

b, (2+b)-(b+1)

=2+b-b-1

=1

c, -(1-2)+(5-c)

=1+5-c

=6-c

d, -(a-c)-(a-b+c)

=-a+c-a+b-c

=-2a+b

bai 2, tim x, biet

a, -x+8= -17

-x=-17-8

-x=-25

x=25

b, 35-x=37

x=35-37

x=-2

c, -19-x= -20

-x=-20+19

-x=-1

x=1

d, 2130-(x+130)+72= -64

2175-(x+130)=-64

-(x+130)=-64-2175

-(x+130)=-2239

x+130=2239

x=2239-130

x=2109

Answer 3

Bài 1: a, (a-1) - (a-3) = a-1-a+3 = 2

         b, (2+b) - (b+1)= 2+b-b-1 =1

         c,-(1-2) + (5-c) = -1+2+5-c = 6-c

         d,-(a-c) - (a-b+c) = -a+c-a+b-c = -2a+b

Bài 2: a, -x + 8 = -17 => -x = -17- 8 = -25

         b, 35 - x = 37 => x = 35 - 37 = -2

         c, -19 - x = -20 => x = -19 + 20 = 1

         d, 2130-(x+130)+72 = -64 => x+130 = 2130+64-72 = 2122 => x= 2122-130 =1992