\(\left(\frac{3x}{7}+1\right)=\frac{-1}{28}.\left(-4\right)\)

\(\left(\frac{3x}{7}+1\right)=\frac{1}{7}\)

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

\(\frac{3x}{7}=\frac{-6}{7}\)

=> 3x = -6

=> x   = -6 : 3

=> x   = -2

Vậy x = -2

\(\left(\frac{3x}{7}+1\right)=\frac{-1}{28}.\left(-4\right)\)

\(\left(\frac{3x}{7}+1\right)=\frac{1}{7}\)

\(\frac{3x}{7}=\frac{1}{7}-1=\frac{-6}{7}\)

\(3x=-6\)

\(=>x=\left(-6\right):3=-2\)

\(\left(\frac{3x}{7}+1\right)=\frac{-1}{28}.\left(-4\right)\)

\(\Rightarrow\left(\frac{3x+7}{7}\right)=\frac{1}{7}\)

=> 3x+7=1

=>3x=-6

=>x=-2

\(\left(\frac{3x}{7}+1\right)\div\left(-4\right)=\frac{-1}{28}\)

                       \(\frac{3x}{7}+1=\frac{-1}{28}\times\left(-4\right)\)

                        \(\frac{3x}{7}+1=\frac{1}{7}\)

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

                                    \(\frac{3x}{7}=\frac{-6}{7}\)

                                     \(3x=\frac{-6}{7}\times7\) 

                                       \(3x=-6\)

                                          \(x=-2\)

Vậy x = -2

tớ ko bít đúng hay sai đâu nha

\(\Leftrightarrow\)\(-\frac{1}{28}\cdot\left(-4\right)\)=\(\frac{3x}{7}+1\)

\(\Leftrightarrow\frac{1}{7}=\frac{3x}{7}+1\)

\(\Leftrightarrow\frac{1}{7}-1=3x:7\)

\(\Leftrightarrow3x:7=-\frac{6}{7}\)

\(\Leftrightarrow3x=\frac{-6}{7}.7\)

\(\Leftrightarrow x=-6:3\)

\(\Leftrightarrow x=-2\)

âm 2 nha bạn

\(\left(\frac{3x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\)

\(\Leftrightarrow\frac{3x+7}{7}.\frac{1}{-4}=\frac{-1}{28}\)

\(\Leftrightarrow-\frac{3x+7}{28}=\frac{-1}{28}\)

\(\Leftrightarrow-\left(3x+7\right)=-1\)

\(\Leftrightarrow3x+7=1\)\(\Leftrightarrow3x=-6\)

\(\Leftrightarrow x=-2\)

\(\left(\frac{3x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\)

\(\Leftrightarrow\frac{3x}{7}+1=\frac{-1}{28}.\left(-4\right)\)

\(\Leftrightarrow\frac{3x}{7}+1=\frac{1}{7}\)

\(\Leftrightarrow\frac{3x}{7}=\frac{-6}{7}\)

\(\Leftrightarrow3x=-6\)

\(\Leftrightarrow x=-2\)

Loan còn lượt cho đúng cho mình không chứ mấy bn kia chắc ko cho đúng đâu?

(3x/7+1):(-4)=-1/28

3x/7+1=-1/28x(-4)

3x/7+1=1/7

3x/7=1/7-1=-6/7

3x=-6

x=-6:3=-2

Vậy x=-2

Chào bạn, bạn hãy theo dõi lời giải của mình nhé! 

Ta có : 

\(\left(\frac{3x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\)

\(=>\frac{3x}{7}+\frac{7}{7}=\frac{-1}{28}.\left(-4\right)=\frac{-1.\left(-4\right)}{28}=\frac{4}{28}=\frac{1}{7}\)

\(=>\frac{3x+7}{7}=\frac{1}{7}\)

\(=>3x+7=1\)

\(=>3x=1-7=-4\)

\(3x=-4:3=\frac{-4}{3}\)

Chuc bạn học tốt!

Chú ý : \(\left|+1\right|\)cũng vẫn là bằng 1

Ta có : \((\frac{3x}{7}\cdot1):(-1)=\frac{-1}{28}\)

\(\Rightarrow(\frac{3x}{7}\cdot1)=\frac{-1}{28}\cdot(-1)\)

\(\Rightarrow(\frac{3x}{7}\cdot1)=\frac{1}{28}\)

\(\Rightarrow\frac{3x}{7}=\frac{1}{28}:1\)

\(\Rightarrow\frac{3x}{7}=\frac{1}{28}\)

\(\Rightarrow3x=\frac{1}{28}\cdot7\)

\(\Rightarrow3x=\frac{1}{4}\)

\(\Rightarrow x=\frac{1}{4}\div3\)

\(\Rightarrow x=\frac{1}{12}\)