Mình sửa đề câu $10$ nha.
$1$) $34 + 4(52-x) = 86$
$⇔ 4(52-x) = 52$
$⇔ 52-x = 13$
$⇔ x = 39$
Vậy $x=39$
$2$) $6(3x-5) - 17 = 79$
$⇔ 6(3x-5) = 96$
$⇔ 3x - 5 = 16$
$⇔ 3x = 21$
$⇔ x = 7$
Vậy $x=7$
$3$) $117 - 5(2x-8) = 67$
$⇔ 5(2x-8) = 50$
$⇔ 2x-8 = 10$
$⇔ 2x = 18$
$⇔ x = 9$
Vậy $x=9$
$4$) $(54-3x):5 = 6$
$⇔ 54-3x = 30$
$⇔ 3x = 24$
$⇔ x = 8$
Vậy `x=8`
$5$) `3636 : (12x - 91) = 36`
`⇔ 12x - 91 = 101`
`⇔ 12x = 192`
`⇔ x = 16`
Vậy `x=16`
$6$) `96 - 3(x+1) = 42`
`⇔ 3(x+1) = 54`
`⇔ x+1 = 18`
`⇔ x = 17`
Vậy `x=17`
$7$) `124 + 2(3x+5) = 140`
`⇔ 2(3x+5) = 16`
`⇔ 3x+5 = 8`
`⇔ 3x = 3`
`⇔ x = 1`
Vậy `x=1`
$8$) `96 : (5x-1) - 17 = 7`
`⇔ 96 : (5x-1) = 24`
`⇔ 5x-1 = 4`
`⇔ 5x = 5`
`⇔ x = 1`
Vậy `x=1`
$9$) `125 - 12(19 - 2x)=65`
`⇔ 12(19-2x) = 60`
`⇔ 19-2x = 5`
`⇔ 2x = 14`
`⇔ x = 7`
Vậy `x=7`
$10$) `128 + 4(3x+5) = 160`
`⇔ 4(3x+5) = 32`
`⇔ 3x+5 = 8`
`⇔ 3x = 3`
`⇔ x = 1`
Vậy `x=1`
$11$) `639 : [3(15:x-2)] = 71`
`⇔ 3(15:x-2) = 9`
`⇔ 15:x - 2 = 3`
`⇔ 15:x = 5`
`⇔ x = 3`
Vậy `x=3`
$12$) `[(4x - 28).3 - 45] : 5 = 3`
`⇔ (4x-28).3 - 45 = 15`
`⇔ (4x-28).3 = 60`
`⇔ 4x-28 = 20`
`⇔ 4x = 48`
`⇔ x = 12`
Vậy `x=12`
$13$) `720 : [41 - (2x-5)] = 2^3 . 5`
`⇔ 720 : [41 - (2x-5)] = 40`
`⇔ 41 - ( 2x-5) = 18`
`⇔ 2x-5 = 23`
`⇔ 2x = 28`
`⇔ x = 14`
Vậy `x=14`
$14$) `42 - [126 : (5x-8) - 7] . 3 = 9`
`⇔ [126 : (5x-8) - 7].3 = 33`
`⇔ 126 : (5x-8) - 7 = 11`
`⇔ 126 : (5x-8) = 18`
`⇔ 5x-8 = 7`
`⇔ 5x = 15`
`⇔ x = 3`
Vậy `x=3`
$15$) `5871 : [928 - (247 - 2x).5] = 57`
`⇔ 928 - (247 - 2x).5 = 103`
`⇔ (247-2x).5 = 825`
`⇔ 247 - 2x = 165`
`⇔ 2x = 82`
`⇔ x = 41`
Vậy `x=41`
$16$) `30 : {175 : [355 - (135 + 5x)]} = 6`
`⇔ 175 : (355 - 135 - 5x) = 5`
`⇔ 220 - 5x = 35`
`⇔ 5x = 185`
`⇔ x = 37`
Vậy `x=37`
$17$) `100 : {250 : [450 - (4x - 2^2 . 25)]} = 20`
`⇔ 250 : (450 - 4x + 100) = 5`
`⇔ 550 - 4x = 50`
`⇔ 4x = 500`
`⇔ x = 125`
Vậy `x=125`
$18$) `(3x-21) : 4 + 108 = 114`
`⇔ (3x-21) : 4 = 6`
`⇔ 3x-21 = 24`
`⇔ 3x = 45`
`⇔ x = 15`
Vậy `x=15`
$19$) `1596 : [728 - (246 - 2x).5] = 42`
`⇔ 728 - (246-2x).5 = 28`
`⇔ (246-2x).5 = 690`
`⇔ 246 - 2x =138`
`⇔ 2x= 108`
`⇔ x = 54`
Vậy `x=54`
$20$) `129 - [532 : (5x-6) - 7].3 = 36`
`⇔ [532 : (5x-6) - 7].3 = 93`
`⇔ 532 : (5x-6) - 7 = 31`
`⇔ 532 : (5x-6) = 38`
`⇔ 5x-6 = 14`
`⇔ 5x = 20`
`⇔ x =4`
Vậy `x=4`
$21$) `[(137 - 4x).3 - 45]:6 = 37`
`⇔ (137-4x).3 - 45 = 222`
`⇔ (137-4x).3 = 267`
`⇔ 137 - 4x = 89`
`⇔ 4x = 48`
`⇔ x = 12`
Vậy `x=12`
$22$) `2/3 + 1/3 : x = 3/5`
`⇔ 1/3 : x = -1/15`
`⇔ x = -5`
Vậy `x=-5`
$23$) `8 2/3 : x - 10 = -8`
`⇔ 26/3 : x = 2`
`⇔ x = 13/3`
Vậy `x=13/3`.
