\(\frac{x+4}{x+1}=\frac{x+5}{x-4}ĐK:x\ne-1;4\)

\(\Leftrightarrow x^2-16=\left(x+1\right)\left(x+5\right)\Leftrightarrow x^2-16=x^2+5x+x+5\)

\(\Leftrightarrow-6x-21=0\Leftrightarrow x=-\frac{21}{6}\)

\(\frac{13}{40}-\frac{11}{47}.\frac{1}{2}+\frac{1}{20}-\)\(\frac{121}{47.72}\)

\(=\left(\frac{13}{40}+\frac{1}{20}\right)-\)\(\left(\frac{11}{47}.\frac{1}{2}+\frac{121}{47.72}\right)\)

\(=\left(\frac{13}{40}+\frac{2}{40}\right)\)\(-\left(\frac{11}{47}.\frac{1}{2}+\frac{11}{47}.\frac{11}{72}\right)\)

\(=\frac{3}{8}-\frac{11}{47}.\left(\frac{1}{2}+\frac{11}{72}\right)\)

\(=\frac{3}{8}-\frac{11}{47}.\frac{47}{72}\)

\(=\frac{3}{8}-\frac{11}{72}\)

\(=\frac{27}{72}-\frac{11}{72}\)

\(=\frac{2}{9}\)

\(\frac{a}{2b+c}=\frac{b}{2c+a}=\frac{c}{2a+b}\Rightarrow\frac{2a}{2b+c}=\frac{2b}{2c+a}=\frac{2c}{2a+b}=\frac{2\left(a+b+c\right)}{3\left(a+b+c\right)}=\frac{2}{3}\)

\(\Rightarrow\frac{2b+c}{2a}=\frac{2c+a}{2b}=\frac{2a+b}{2c}=\frac{3}{2}\)

\(\Rightarrow\frac{2b+c}{2a}+\frac{2c+a}{2b}+\frac{2a+b}{2c}=\frac{3.3}{2}=4,5\)

Bạn ơi trẩu quá đừng đăng lung tung ạ:v

bạn ơi sức đè kháng kém là do bạn không chơi đồ đấy bạn ạ:)