Question

Cho biểu thức

A=2x/x²-25+5/5-x-1/x+5 ( với x khác 5 và x khác -5)

1 rút gọn biểu thức

Answer 1

\(A=\frac{2x}{x^2-25}+\frac{5}{5-x}-\frac{1}{x+5}\\ A=\frac{2x}{\left(x+5\right)\left(x-5\right)}+\frac{-5}{x-5}-\frac{1}{x+5}\\ A=\frac{2x}{\left(x+5\right)\left(x-5\right)}+\frac{-5\left(x+5\right)}{\left(x+5\right)\left(x-5\right)}-\frac{1\left(x-5\right)}{\left(x+5\right)\left(x-5\right)}\\ A=\frac{2x}{\left(x+5\right)\left(x-5\right)}+\frac{-5x-25}{\left(x+5\right)\left(x-5\right)}-\frac{x-5}{\left(x+5\right)\left(x-5\right)}\\ A=\frac{2x-5x-25-x+5}{\left(x+5\right)\left(x-5\right)}\)

\(A=\frac{-4x-20}{\left(x+5\right)\left(x-5\right)}\\ A=\frac{-4\left(x+5\right)}{\left(x+5\right)\left(x-5\right)}\\ A=\frac{-4}{x-5}\)