Question

[tuấn phong phạm quang]

-3(\(\dfrac{x}{3}\) -  \(\dfrac{1}{4}\))-\(\dfrac{1}{3}\)(3x + \(\dfrac{1}{2}\))=7x

Answer 1

[乇尺尺のﾚ]

\(-3\left(\dfrac{x}{3}-\dfrac{1}{4}\right)-\dfrac{1}{3}\left(3x+\dfrac{1}{2}\right)=7x\\ \Rightarrow-\dfrac{3x}{3}+\dfrac{3}{4}-\dfrac{3x}{3}-\dfrac{1}{6}=7x\\ \Rightarrow-x+\dfrac{3}{4}-x-\dfrac{1}{6}=7x\\ \Rightarrow-x+\dfrac{3}{4}-x-\dfrac{1}{6}-7x=0\\ \Rightarrow\left(-x-x-7x\right)+\left(\dfrac{3}{4}-\dfrac{1}{6}\right)=0\\ \Rightarrow\left[x\left(-1-1-7\right)\right]+\left(\dfrac{3.3}{4.3}-\dfrac{1.2}{6.2}\right)=0\\ \Rightarrow-9x+\left(\dfrac{9}{12}-\dfrac{2}{12}\right)=0\\ \Rightarrow-9x+\dfrac{7}{12}=0\\ \Rightarrow-9x=\dfrac{-7}{12}\\ \Rightarrow x=-\dfrac{7}{12}:\left(-9\right)\\ \Rightarrow x=\dfrac{-7}{12}\cdot\dfrac{-1}{9}\\ \Rightarrow x=\dfrac{7}{108}\)

Answer 2

[Nguyễn Lê Phước Thịnh]

=>-x+3/4-x-1/6=7x

=>-9x=-3/4+1/6=-7/12

=>x=7/108