Bài `2:`
`a, (2x-1)^3=-27`
`=> (2x-1)^3=(-3)^3`
`=> 2x-1=-3`
`=> 2x=(-3)+1`
`=> 2x=-2`
`=> x=(-2):2`
`=> x=-1`
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`b,(3x+5)^2=9`
`=> (3x+5)^2=3^2`
`=> 3x+5=3`
`=> 3x=3-5`
`=> 3x=-2`
`=> x=(-2):3`
`=> x=-2/3`
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`c, (5x-25)^123=0`
`=> (5x-25)^123=0^123`
`=> 5x-25=0`
`=> 5x=0+25`
`=> 5x=25`
`=> x=25:5`
`=> x=5`
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`(-4/5)^3=((-4)^3/5^3)=-64/125`
`(2/3-5/4)^4=(-7/12)^4=((-7)^4/12^4)=2401/20736`
