bai nhiu qua troi

tự làm đi

Tớ không biết xin lỗi cậu nhé

dễ mà bn, ta sử dụng tính chất phân phối của phép trừ đối với phép nhân:

0,5=\(\frac{1}{2}\)

 \(\frac{1}{2}\)x - \(\frac{2}{3}\)x = \(\frac{7}{12}\)

 x ( \(\frac{1}{2}\)- \(\frac{2}{3}\)) = \(\frac{7}{12}\)

 x . \(\frac{-1}{6}\)= \(\frac{7}{12}\)

x = \(\frac{7}{12}\): \(\frac{-1}{6}\)

x = \(\frac{7}{12}\). -6

x = \(-3\frac{1}{2}\)

( like cho mk lunk ha, bài này dễ, kiểm tra lại ha! Nếu mk làm sai thì còn sửa nữa!!!!!!!!!)

tốt đấy

\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow x\left(\frac{1}{2}-\frac{2}{3}\right)=\frac{7}{12}\Rightarrow x\cdot\left(\frac{3}{6}-\frac{4}{6}\right)=\frac{7}{12}\)

\(\Rightarrow x\cdot\left(-1\right)=\frac{7}{12}\Rightarrow x=\frac{7}{12}:\left(-1\right)=\frac{7}{-12}\)

\(c,\frac{\left(x-5\right)}{12}\cdot\frac{9}{29}=\frac{-6}{29}\Rightarrow\frac{\left(x-5\right)}{12}=\frac{-6}{29}:\frac{9}{26}\)

\(\frac{\Rightarrow\left(x-5\right)}{12}=\frac{-6}{9}=\frac{-2}{3}\Rightarrow x-5=-\frac{2}{3}\cdot12\)

\(\Rightarrow x-5=\frac{-24}{3}=-8\Rightarrow x=-8+5=-3\)

\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow-\frac{1}{6}x=\frac{7}{12}\)

\(\Rightarrow x=-\frac{7}{2}\)

\(c,\frac{x-5}{12}\cdot\frac{9}{29}=-\frac{6}{29}\)

\(\Rightarrow\frac{x-5}{12}=-\frac{2}{3}\)

\(\Rightarrow x-5=12.\left(-\frac{2}{3}\right)\)

\(\Rightarrow x-5=-8\)

\(\Rightarrow x=-3\)

b)\(\frac{-8}{17}+\frac{5}{17}< \frac{x}{17}< \frac{-6}{17}+\frac{9}{17}\)\(\left(x\in Z\right)\)

\(\Rightarrow\frac{-3}{17}< \frac{x}{17}< \frac{3}{17}\)

\(\Rightarrow-3< x< 3\)

\(\Rightarrow x\in\left\{-2;-1;0;1;2\right\}\)

Vậy \(x\in\left\{-2;-1;0;1;2\right\}\)

x. (0,5-2/3)= 5/12

x. -1/6= 5/12

x= 5/12 : -1/6

x= -5/2

\(0,5x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow x\left(0,5-\frac{2}{3}\right)=\frac{7}{12}\)

\(\Rightarrow-\frac{1}{6}x=\frac{7}{12}\)

\(\Rightarrow x=-\frac{7}{2}=-3,5\)

\(\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Leftrightarrow-\frac{1}{6}x=\frac{7}{12}\)

\(\Leftrightarrow x=\frac{7}{12}:-\frac{1}{6}\)

\(\Leftrightarrow x=-\frac{7}{2}\)

~~~~~~~~~~~~~~~~~~~~~

í mình nhầm: 

 0,5x - 2/3x = 7/12

= -0,5/3x = 7/12

x = 7/12 : -0,5/3

x= 21/-6 = 7/-2

0,5x - 2/3x = 7/12

(0,5 - 2/3)x = 7/12

-1/6x = 7/12

x = -3,5

tớ ko biết đúng hay sai đâu