`a)(x-1/2)^3 = -27/8`
`=>(x-1/2)^3= (-3/2)^3`
`=>x-1/2= -3/2`
`=> x=-3/2+1/2`
`=>x=-1`
Vậy....
`b)(x-1)/(-4)=(-9)/(x-1)`
`=> (x-1).(x-1)=(-9).(-4)`
`=>(x-1)^2= 6^2`
`=>x-1=6=>x=7`
Vậy...
`c) 2/5 -(1/10 -x)=(-2/5 -1/5)^2`
`=> 2/5 -1/10 +x =(-9/10)^2`
`=> 2/5 -1/10 +x =81/100`
`=>3/10 +x = 81/100`
`=>x= 81/100 -3/10 =51/100`
Vậy...
`d)2/5 -3/5(x-2)= (-1/2)^3 -(3/4)^3 .(-2)^2`
`=> 2/5 - (3x)/5 .3/5 .(-2)= (-1/2)^3 -(3/4)^3 .(-2)^2`
`=>2/5 -(3x)/5 +6/5= -1/8 -27/64 .(-2)^2`
`=>8/5-(3x)/5= -1/8 - (27.4)/64`
`=>8/5 -(3x/5)= -1/8 - 27/16`
`=>8/5 -(3x)/5 = -29/16`
`=> 8-(3x) = -145/16`
`=>3x= 273/16`
`=>x=91/16`
Vậy....
