Question

7) | 1/4x - 3/4| = 4/ 5 x- 2/5

8) | 2x-1| =x

9) | x+ 2| = 2x

Answer 1

câu 7 viết v k hiểu 

câu 8: |2x-1|=x<=> \(\left[\begin{array}{nghiempt}2x-1=x\\2x-1=-x\end{array}\right.\)=> x=1 hoặc x=1/3

câu 9 |x+2|=2x<=> \(\left[\begin{array}{nghiempt}x+2=-2x\\x+2=2x\end{array}\right.\)=> x=-2/3 hặc x=-1/2

Answer 2

Câu 7 :

\(\left|\frac{1}{4}x-\frac{3}{4}\right|=\frac{4}{5}x-\frac{2}{5}\)

\(\Rightarrow\) \(\left[\begin{array}{nghiempt}-\frac{1}{4}x+\frac{3}{4}=\frac{4}{5}x-\frac{2}{5}\\\frac{1}{4}x-\frac{3}{4}=\frac{4}{5}x-\frac{2}{5}\end{array}\right.\) \(\Leftrightarrow\) \(\left[\begin{array}{nghiempt}\frac{21}{20}x=\frac{23}{20}\\\frac{11}{20}x=-\frac{7}{20}\end{array}\right.\)

\(\Leftrightarrow\)  \(\left[\begin{array}{nghiempt}x=\frac{23}{21}\\x=-\frac{7}{11}\end{array}\right.\)

Cây 8) 9) dễ hơn, bạn làm tương tự