ĐKXĐ: x<>0; x<>-5
a: \(A=\frac{x^2+2x}{2x+10}+\frac{x-5}{x}-\frac{5x-50}{2x\left(x+5\right)}\)
\(=\frac{x\left(x^2+2x\right)}{2x\left(x+5\right)}+\frac{\left(x-5\right)\cdot\left(x+5\right)\cdot2}{2x\left(x+5\right)}-\frac{5x-50}{2x\left(x+5\right)}\)
\(=\frac{x^3+2x^2+2x^2-50-5x+50}{2x\left(x+5\right)}=\frac{x^3+4x^2-5x}{2x\left(x+5\right)}\)
\(=\frac{x\left(x^2+4x-5\right)}{2x\left(x+5\right)}=\frac{x^2+4x-5}{2\left(x+5\right)}\)
\(=\frac{\left(x+5\right)\left(x-1\right)}{2\left(x+5\right)}=\frac{x-1}{2}\)
b: A=1
=>\(\frac{x-1}{2}=1\)
=>x-1=2
=>x=3(nhận)
A=-3
=>\(\frac{x-1}{2}=-3\)
=>x-1=-6
=>x=-5(loại)
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