\(\frac{1}{6}=\frac{x}{18}\Rightarrow x=3\)

\(\frac{x}{8}=-\frac{1}{4}\Rightarrow x=-2\)

\(\frac{4}{-5}=\frac{x}{10}\Rightarrow x=-8\)

\(\frac{11}{5}=-\frac{22}{x}\Rightarrow x=-10\)

\(\frac{x}{8}=\frac{8}{x}\Rightarrow x^2=64\Rightarrow x=8\)

\(\frac{x}{-11}=-\frac{11}{x}\Rightarrow x^2=121\Rightarrow x=11\)

#H

\(\frac{1}{4}:\left(\frac{x}{4}+\frac{\left(-2\right)}{7}+\frac{2}{8}\right)=\frac{\left(-1\right)}{14}\)

\(\frac{1}{4}:\left(\frac{x}{4}+\frac{\left(-1\right)}{28}\right)=\frac{\left(-1\right)}{14}\)

\(\frac{x}{4}+\frac{\left(-1\right)}{28}=\frac{1}{4}:\frac{\left(-1\right)}{14}\)

\(\frac{x}{4}+\frac{\left(-1\right)}{28}=\frac{-7}{2}\)

\(\frac{x}{4}=\frac{-7}{2}-\frac{\left(-1\right)}{28}\)

\(\frac{x}{4}=\frac{-97}{28}\)

\(\frac{7x}{28}=\frac{-97}{28}\)

\(\Rightarrow7x=-97\)

\(\Rightarrow x=-97:7\)

\(\Rightarrow x=\frac{-97}{7}\)

Váy \(x=\frac{-97}{7}\)

Nhớ k cho mk nha  Le Ha Trang

\(\dfrac{x}{x+2}-\dfrac{x^3}{x^3+8}\cdot\dfrac{x^2-2x+4}{x^2-4}\\ =\dfrac{x}{x+2}-\dfrac{x^3}{\left(x+2\right)\left(x^2-2x+4\right)}\cdot\dfrac{x^2-2x+4}{\left(x-2\right)\left(x+2\right)}\\ =\dfrac{x}{x+2}-\dfrac{x^3}{\left(x+2\right)^2\left(x-2\right)}\\ =\dfrac{x\left(x^2-4\right)-x^3}{\left(x+2\right)^2\left(x-2\right)}=\dfrac{x^3-4x-x^3}{\left(x+2\right)^2\left(x-2\right)}=\dfrac{-4x}{\left(x+2\right)^2\left(x-2\right)}\)

       Câu hỏi của Nguyễn Hữu Hưng       

\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x.\left(x+3\right)}=\frac{101}{1540}\)

\(\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{x.\left(x+3\right)}=\frac{303}{1540}\)

\(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\frac{1}{x+3}=\frac{1}{308}\)

\(\Rightarrow x+3=308\)

\(x=305\)

\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x.\left(x+30+\frac{101}{1540}\right)}\)

Phải gì không .

ghi nham la the nay

1 phan 5 nhan 8 cong 1 phan 8 nhan 11 cong 1 phan 11 nhan 14 +..........+1 phan x nhan (x+3)=101 phan 1540

\(\frac{2}{5^{x-2}}\)=\(\frac{8}{12}\)

=>2.12=8.5^x-2

    24   =8.5^x-2

mà số nào nhân với 5 cũng cón số hàng đơn vị là 5 và 0

mà 8.5^x-2=24

=> x\(\in\)tập hợp rỗng