ĐKXĐ: x≠0; x≠5; x≠-5
MTC=x(x+5)(x-5)
Ta có: \(\frac{2}{x^2-25}-\frac{1}{x^2+5x}=\frac{4}{x\left(x-5\right)}\)
\(\Leftrightarrow\frac{2}{\left(x-5\right)\left(x+5\right)}-\frac{1}{x\left(x+5\right)}-\frac{4}{x\left(x-5\right)}=0\)
\(\Leftrightarrow\frac{2x}{x\left(x-5\right)\left(x+5\right)}-\frac{x-5}{\left(x-5\right)\cdot x\cdot\left(x+5\right)}-\frac{4\left(x+5\right)}{x\left(x-5\right)\left(x+5\right)}=0\)
\(\Leftrightarrow2x-\left(x-5\right)-4\left(x+5\right)=0\)
\(\Leftrightarrow2x-x+5-4x-20=0\)
\(\Leftrightarrow-3x-15=0\)
\(\Leftrightarrow-3x=15\)
hay x=-5(ktm)
Vậy: x∈∅
