2 câu trả lời
`[124 - (20- 4x)] : 30 + 7 = 11`
`=> [124 - (20- 4x)] : 30 = 11 - 7`
`=> [124 - (20 - 4x)] : 30 = 4`
`=> 124 - (20 - 4x) = 4 . 30`
`=> 124 - (20 - 4x) = 120`
`=> 20 - 4x = 124 - 120`
`=> 20 - 4x = 4`
`=> 4x = 20 - 4`
`=> 4x = 16`
`=> x = 16 : 4`
`=> x = 4`
Vậy `x = 4`
`#dtkc`
`[ 124 - ( 20 - 4x ) ] : 30 + 7 = 11`
`=> [ 124 - ( 20 - 4x ) ] : 30 = 11 - 7`
`=> [ 124 - ( 20 - 4x ) ] : 30 = 4`
`=> 124 - ( 20 - 4x ) = 4. 30`
`=> 124 - ( 20 - 4x ) = 120`
`=> 20 - 4x = 124 - 120`
`=> 20 - 4x = 4`
`=> 4x = 20 - 4`
`=> 4x = 16`
`=> x = 16 : 4`
`=> x = 4`
$Vậy$ `x = 4`