\(A=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}\right):\frac{2x}{5x-5}\)
\(A=\left[\frac{x+1}{x-1}-\left(\frac{x-1}{x+1}\right)\right]:\frac{2x}{5x-5}\)
\(A=\frac{20x^2-20x}{2x^3-2x}\)
\(A=\frac{20x-20}{2x^2-2}\)
\(A=\frac{10x-10}{x^2-1}\)
\(A=\frac{10\left(x-1\right)}{\left(x+1\right)\left(x-1\right)}\)
\(A=\frac{10}{x+1}\)
Để A = 2, ta có:
\(A=\frac{10}{x+1}=2\)
\(\Leftrightarrow10=2x+2\)
\(\Leftrightarrow2x+2=10\)
\(\Leftrightarrow2x=10-2\)
\(\Leftrightarrow2x=8\)
\(\Leftrightarrow x=4\)
Vậy: để A = 2 thì giá trị của x là 4
