b1:bỏ ngoặc rồi tinh hợp lí
1) -( -66)+34+(-73)-27+99 2)54-(45-30+54)-30+5 3)42-56+33-(33-56+42)
4)50-(47+50-18)+(47-18) 5) |25-24-10|-(28-30+4) 6)-(-73)+(44-94+27)+94
7) (-33+180-75)-(180+25) 8)120-(-92+120-18)-92
B2:tìm x biết
1)x+18=6-2x 2)17-x=7-6x 3)x+15=20-4x 4)7x-4=20+3x 5)-12+x=5x-20 6)4x-18=x+27
7) 2.(x-5)-3.(x+7)=14 8)5.(x-6)-2.(x+3)=12 9)-7.(5-x)-2.(x-10)=15 10)3. ( x - 4 ) - ( 8 - x )=12
11)4.(x-5)-(x+7)=-19 12)7.(x-3)-5.(3-x)=11x-5
B2:tìm x biết
1)x+18=6-2x
<=> 3x=-12
<=> x= -4
2)17-x=7-6x
<=>5x=-10
<=>x=-2
3)x+15=20-4x
<=>5x=5
<=>x=1
4)7x-4=20+3x
<=> 4x=24
<=>x=6
5)-12+x=5x-20
<=>4x=8
<=>x=2
6)4x-18=x+27
<=>3x=45
<=>x=9
7) 2.(x-5)-3.(x+7)=14
<=>2x-10-3x-21=14
<=>-x=14+10+21=45
<=>x=-45
8)5.(x-6)-2.(x+3)=12
<=>5x-30-2x-6=12
<=>3x=48
<=>x=12
9)-7.(5-x)-2.(x-10)=15
<=>-35+7x-2x+20=15
<=>5x=30
<=>x=6
10)3. ( x - 4 ) - ( 8 - x )=12
<=>3x-12-8+x=12
<=>4x=32
<=>x=8
11)4.(x-5)-(x+7)=-19
<=>4x-20-x-7=-19
<=>3x=8
<=>x=8/3
12)7.(x-3)-5.(3-x)=11x-5
<=>7x-21-15+5x=11x-5
<=>x=31
b1:bỏ ngoặc rồi tinh hợp lí
1) -( -66)+34+(-73)-27+99=66+34-73-27+99 =100-100+99=99
2)54-(45-30+54)-30+5=54-45+30-54-30+5=-45+5=-40
3)42-56+33-(33-56+42)=42-56+33-33+56-42=0
4)50-(47+50-18)+(47-18)=50-47-50+18+47-18=0
5) |25-24-10|-(28-30+4)=9-28+30-4=39-32=7
6)-(-73)+(44-94+27)+94=73+44-94+27+94=100+44=144
7) (-33+180-75)-(180+25)=-33+180-75-180-25=-100-33=-133
8)120-(-92+120-18)-92=120+92-120+18=108