( 6x – 84 ) : 2 – 72 =201
91 – 3 . x = 61
72 : (4x -3 )= 8
[( 6x -72) :2 -84] . 28 = 5628
25 + 3 ( x – 8 ) = 106
( 6x – 84 ) : 2 – 72 =201
91 – 3 . x = 61
72 : (4x -3 )= 8
[( 6x -72) :2 -84] . 28 = 5628
25 + 3 ( x – 8 ) = 106
Đáp án:
Giải thích các bước giải:
a, `( 6x – 84 ) : 2 – 72 = 201`
`( 6x – 84 ) : 2 = 201 + 72`
`( 6x – 84 ) : 2 = 273`
`6x – 84 = 273 . 2`
`6x – 84 = 546`
`6x = 546 + 84`
`6x = 630`
`x = 630 : 6`
⇒ `x = 105`
Vậy x = 105
b, `91 – 3 . x = 61`
`3 . x = 91 – 61`
`3 . x = 30`
`x = 30 : `3
⇒ `x = 10`
Vậy x = 10
c, `72 : ( 4x – 3 ) = 8`
`4x – 3 = 72 : 8`
`4x – 3 = 9`
`4x = 9 + 3`
`4x = 12`
`x = 12 : 4`
⇒ `x = 3`
Vậy x = 3
d, `[( 6x -72) : 2 -84] . 28 = 5628`
`[( 6x -72) : 2 -84] = 5628 : 28`
`[( 6x -72) : 2 -84] = 201`
`( 6x -72) : 2 = 201 + 84`
`( 6x – 72) : 2 = 285`
`6x – 72 = 285 . 2`
`6x – 72 = 570`
`6x = 570 + 72`
`6x = 642`
`x = 642 : 6`
⇒ `x = 107`
Vậy x = 107
e, `25 + 3 ( x – 8 ) = 106`
`3 ( x – 8 ) = 106 – 25`
`3 ( x – 8 ) = 81`
`x – 8 = 81 : 3`
`x – 8 = 27`
`x = 27 + 8
⇒ `x = 35`
Vậy x = 35
Đáp án:
$1:X=105$
$2:x=10$
$3:x=3$
$4:x=107$
$5:x=35$
Giải thích các bước giải:
$1:(6x-84)÷2-72=201$
$⇒(6x-84)÷2=201+72=273$
$⇒6x-84=273×2=546$
$⇒6x=546+84=630$
$⇒x=630÷6=105$
$2:91-3×x=61$
$⇒3×x=91-61=30$
$⇒x=30÷3=10$
$3:72÷(4x-3)=8$
$⇒4x-3=72÷8=9$
$⇒4x=9+3=12$
$⇒x=12÷4=3$
$4:[(6x-72)÷2-84]×28=5628$
$⇒(6x-72)÷2-84=5628÷28=201$
$⇒(6x-72)÷2=201+84=285$
$⇒6x-72=285×2=570$
$⇒6x=570+72=642$
$⇒x=642÷6=107$
$5:25+3×(x-8)=106$
$⇒3×(x-8)=106-25=81$
$⇒x-8=81÷3=27$
$⇒x=27+8=35$