(5x+3)$\frac{3x+11}{4}$-$\frac{x-7}{12}$=0 giải phương trình

Đáp án:

`(5x+3)(\frac{3x+11}{4}-\frac{x-7}{12})=0`
`<=> (5x+3)[\frac{3(3x+11)}{12}-\frac{x-7}{12}]=0`
`<=> (5x+3)(\frac{3x+33}{12}-\frac{x-7}{12})=0`
`<=> (5x+3).\frac{3x+3-x+7}{12}=0`
`<=> (5x+3).\frac{2x+10}{12}=0`
`<=> (5x+3).\frac{x+5}{6}=0`
`<=> (5x+3)(x+5)=0`
`<=> [(5x+3=0),(x+5=0):}`
`<=> [(x=-3/5),(x=-5):}`
Vậy `S={-5;-3/5}`  

Answer

`(5x + 3) . ({3x + 11}/4 - {x - 7}/12) = 0`

`<=> (5x + 3) . ({3 . (3x + 11)}/{3 . 4} - {x - 7}/12) = 0`

`<=> (5x + 3) . ({9x + 33}/{12} - {x - 7}/12) = 0`

`<=> (5x + 3) . ({9x + 33 - x + 7}/{12}) = 0`

`<=> (5x + 3) . ({8x + 40}/{12}) = 0`

`<=>` $\left[\begin{matrix} 5x + 3 = 0\\ \dfrac{8x + 40}{12} = 0\end{matrix}\right.$

`<=>` $\left[\begin{matrix} 5x = 0 - 3\\ 8x + 40 = 0\end{matrix}\right.$

`<=>` $\left[\begin{matrix} 5x = - 3\\ 8x = -40\end{matrix}\right.$

`<=>` $\left[\begin{matrix} x = - 3 : 5\\ x = -40 : 8\end{matrix}\right.$

`<=>` $\left[\begin{matrix} x = \dfrac{-3}{5}\\ x = -5\end{matrix}\right.$

Vậy `S = {{-3}/5 ; -5}`