I.Trắc nghiệm
B1
1Đ
2S
3Đ
4Đ
B2
1a
2c
3c
4a
II.Tự luận
B1
a)-2374-597+2597+1374+2018=(-2374+1374)+[2597+(-597)]+2018=1000+2000+2018=5018
b)-47.43+(-47).56+(-47)=-47.43+(-47).56+(-47).1=-47.(43+56+1)=-47.100=-4700
c)195-(2.33-100/52)=195-(2.27-100/25)=195-(54-4)=195-50=145
B2
a)(3-x)+10=-15
3-x=-15-10
3-x=-15+(-10)
3-x=-25
x=3-(-25)
x=3+25
x=28
Vậy x =28
b)10-3(x-1)=-5
3(x-1)=10-(-5)
3(x-1)=10+5
3(x-1)=15
x-1=15/3
x-1=5
x=5+1
x=6
Vậy x =6
c)-12-|5-x|=-14
|5-x|=-12-(-14)
|5-x|=-12+14
|5-x|=2
=>5-x=2 hoặc 5-x=-2
Th1:5-x=2
x=5-2
x=3
Th2:5-x=-2
x=5-(-2)
x=5+2
x=7
Vậy x=3 hoặc x=7
B3
a)A=(-a-b+c)-(-a-b-c)-2b
=-a-b+c-(-a)+b+c-2b
=-a+(-b)+c+a+b+c-2b
=(-a+a)+(-b+b)+(c+c)-2b
=0+0+2c-2b
=2c-2b
b)Sau khi thay ta đc:
A=[-2018-(-1)+(-2)]-[-2018-(-1)-(-2)]-2.(-1)
=-2018-(-1)+(-2)-(-2018)+(-1)+(-2)-2.(-1)
=-2018+1+(-2)+2018+(-1)+(-2)-2.(-1)
=(-2018+2018)+[1+(-1)]+[-2+(-2)]-2.(-1)
=0+0+(-4)-(-2)
=-4+2
=-2
Vậy a=-2
