nhanh lên 15p nữa thoi

Bài `5:`

`a, 70-5.(x-3)=45`

`=> 5.(x-3)=70-45`

`=> 5.(x-3)=25`

`=> x-3=25:5`

`=> x-3=5`

`=> x=5+3`

`=> x=8`

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`b, 12+(5+x)=20`

`=> 5+x=20-12`

`=> 5+x=8`

`=> x=8-5`

`=> x=3`

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`c, 130-(100+x)=25`

`=> 100+x=130-25`

`=> 100+x=105`

`=> x=105-100`

`=> x=5`

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`d, 175+(30-x)=200`

`=> 30-x=200-175`

`=> 30-x=25`

`=> x=30-25`

`=> x=5`

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`e, 5.(x+12)+22=92`

`=> 5.(x+12)=92-22`

`=> 5.(x+12)=70`

`=> x+12=70:5`

`=> x+12=14`

`=> x=14-12`

`=> x=2`

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`f, 95-5.(x+2)=45`

`=> 5.(x+2)=95-45`

`=> 5.(x+2)=50`

`=> x+2=50:5`

`=> x+2=10`

`=> x=10-2`

`=> x=8`

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`g, 10+2x=4^5:4^3`

`=> 10+2x=4^2`

`=> 10+2x=16`

`=> 2x=16-10`

`=> 2x=6`

`=> x=6:2`

`=> x=3`

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`h, 14x+54=82`

`=> 14x=82-54`

`=> 14x=28`

`=> x=28:14`

`=> x=2`

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`i, 15x-133=17`

`=> 15x=17+133`

`=> 15x=150`

`=> x=150:15`

`=> x=10`

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`j, 155-10.(x+1)=55`

`=> 10.(x+1)=155-55`

`=> 10.(x+1)=100`

`=> x+1=100:10`

`=> x+1=10`

`=> x=10-1`

`=> x=9`

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`k, 6.(x+2^3)+40=100`

`=> 6.(x+8)=100-40`

`=> 6.(x+8)=60`

`=> x+8=60:6`

`=> x+8=10`

`=> x=10-8`

`=> x=2`

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`l, 2^2.(x+3^2)-5=55`

`=> 4.(x+9)-5=55`

`=> 4.(x+9)=55+5`

`=> 4.(x+9)=60`

`=> x+9=60:4`

`=> x+9=15`

`=> x=15-9`

`=> x=6`