`1) ( 2x + 1) - 7 = 14`
`( 2x +1) = 14 + 7`
`2x + 1 = 21`
`2x = 21 - 1`
`2x = 20`
`x = 20 : 2`
`x = 10`
Vậy `x = 10`
``
`2) 3( x + 1) - 32 = 67`
`3( x + 1) = 67 + 32`
`3( x + 1) = 99`
`(x + 1) = 99 : 3`
`x + 1 = 33`
`x = 33 - 1`
`x = 32`
Vậy `x = 32`
``
`3)x . 4^2 - 18 : 3^2 = 78`
`x . 16 - 18 : 9 = 78`
`x . 16 - 2 = 78`
`x . 16 = 78 + 2`
`x . 16 = 80`
`x = 80 : 16`
`x = 5`
Vậy `x = 5`
``
`4) 5^3 . x + 100 = 125`
`125 . x + 100 = 125`
`125 . x = 125 - 100`
`125 . x = 25`
`x =25 : 125`
`x =0,2`
Vậy `x = 0,2`
``
`5) 415 - 9(x + 2) =2^2 . 5^2`
`415 - 9( x + 2) = 10^2`
`415 - 9( x + 2) = 100`
`9( x + 2) = 415 - 100`
`9( x + 2) = 315`
`( x + 2) = 315 : 9`
`x + 2 = 35`
`x = 35 - 2`
`x = 33`
Vậy `x = 33`
``
`6) x - 6 - ( 48 - 24 . 2 : 6 - 3) = 100`
`x - 6 - ( 48 - 48 : 6 - 3) = 100`
`x - 6 - ( 48 - 8 - 3) = 100`
`x - 6 - ( 40 - 3) = 100`
`x - 6 - 37 = 100`
`x - ( 6 + 37) = 100`
`x - 43 = 100`
`x = 100 + 43`
`x = 143`
Vây `x = 143`
``
`7) 20 - [ 7( x - 3) + 4] = 2`
`[ 7( x - 3) + 4] = 20 - 2`
` 7( x - 3) + 4 = 18`
`7( x - 3) = 18 - 4`
`7( x - 3) = 14`
`( x - 3) = 14 : 7`
`x - 3 = 2`
`x = 2 + 3`
`x = 5`
Vậy `x = 5`
``
`8) [( 6x - 39) : 3] . 28 = 5628`
`[( 6x - 39) : 3] = 5628 : 28`
`( 6x - 39) : 3 = 201`
`( 6x - 39) = 201 . 3`
`6x - 39 = 603`
`6x = 603 + 39`
`6x = 642`
`x = 642 : 6`
`x = 107`
Vậy `x = 107`
`#caty09`
