Bài 4 :
`b,123.25 - 5. ( 2345 - x : 11 ) = 17. 25`
`-> 3075 - 5.(2345 - x : 11) = 425`
`-> 5.(2345 - x : 11) = 2650`
`-> 2345 - x : 11 = 530`
`-> x : 11 = 1815`
`-> x = 165`
Vậy `x=165`
`c, 2345 - 156 : ( 3 . x - 47 ) = 1153 . 3`
`-> 2345 - 156 : ( 3 . x - 47 ) = 3459`
`-> 156 : ( 3 . x - 47 ) = -1114`
`-> 3. x - 47 = -78/557`
`-> 3x = 26101/557`
`-> x ~~ 15,62`
`d, ( 86 : x -14 ) : 29 + 1140 : 76 = 16`
`-> ( 86 : x -14 ) : 29 + 15 = 16`
`-> ( 86 : x -14 ) : 29 = 1`
`-> 86 : x -14 = 29`
`-> 86 : x = 43`
`-> x = 2`
Vậy `x = 2`
`e, 3.( x + 16 ) -2x - 18 =60`
`-> 3x + 48 - 2x - 18 =60`
`-> 3x + 48 - 2x = 78`
`-> x + 48= 78`
`->x = 30`
Vậy `x = 30`
`f, (3.x - 36 ).( 72- 432 : x )+ 19 . 54 =27.38`
`-> (3.x - 36 ).( 72- 432 : x )+ 1026 =1026`
`-> (3.x - 36 ).( 72- 432 : x ) = 0`
`->` $\left[\begin{matrix} 3x - 36 = 0\\ 72 - 432 : x = 0\end{matrix}\right.$
`->` $\left[\begin{matrix} 3x = 36\\ 432 : x = 72\end{matrix}\right.$
`->` $\left[\begin{matrix} x = 12\\ x = 6\end{matrix}\right.$
Vậy `x in {12,6}`
