Ответ:
а)
\(\left(\frac{x}{x+1}+1\right)\cdot\frac{x+1}{2x-1}=\frac{2x+1}{x+1}\cdot\frac{x+1}{2x-1}=\frac{2x+1}{2x-1}.\)
б)
\(1-\frac1{1-y}=\frac{-y}{1-y}.\)
\(\frac{5y^2}{1-y^2}:\frac{-y}{1-y}=\frac{5y^2}{(1-y)(1+y)}\cdot\frac{1-y}{-y}=-\frac{5y}{1+y}.\)
в)
\(\frac{4a}{2-a}-a=\frac{4a-a(2-a)}{2-a}=\frac{a(a+2)}{2-a}.\)
\(\frac{a(a+2)}{2-a}:\frac{a+2}{a-2}=-a.\)
г)
\(x+\frac{x}{2-x}=\frac{x(3-x)}{2-x}.\)
\(\frac{x-2}{x-3}\cdot\frac{x(3-x)}{2-x}=x.\)
Ответ: а) \(\frac{2x+1}{2x-1}\); б) \(-\frac{5y}{1+y}\); в) \(-a\); г) \(x\).
