$\dfrac{4x + 3}{5}$`-`$\dfrac{6x - 2 }{7}$`=`$\dfrac{5x + 4}{3}$`+ 3`

Đáp án: `- 2` 

Giải thích các bước giải:

$\dfrac{4x + 3}{5}$`-`$\dfrac{6x - 2 }{7}$`=`$\dfrac{5x + 4}{3}$`+ 3`

`<=>`$\dfrac{7( 4x + 3 ) }{35}$`-`$\dfrac{5( 6x - 2 ) }{35}$`=`$\dfrac{5x + 4}{3}$`+ 9/3`

`<=>`$\dfrac{28x + 21 - 30x + 10}{ 35}$`=`$\dfrac{5x + 4 + 9}{3}$

`<=>`$\dfrac{- 2x + 31 }{35}$`=`$\dfrac{5x + 3}{5}$

`<=>`$\dfrac{3( - 2x + 31 )}{ 35}$`=`$\dfrac{35( 5x + 13 )}{105}$

`=> 3( - 2x + 31 ) = 35 ( 5x + 13 )`

`<=> - 6x + 93 = 175x + 455`

`<=> - 6x - 175x = 455 - 93`

`<=> - 181x = 362`

`<=> x = - 2`

Vậy `S = { - 2 }`