\(a,5x-10=0\\ \Leftrightarrow5x=10\\ \Leftrightarrow x=2\\ b,7x-6=2x+9\\ \Leftrightarrow7x-2x=9+6\\ \Leftrightarrow5x=15\\ \Leftrightarrow x=3\\ c,\left(x+5\right)\left(4x-9\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+5=0\\4x-9=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-5\\x=\dfrac{3}{2}\end{matrix}\right.\\ d,\dfrac{x+3}{x+1}+\dfrac{x-3}{x}=2\\ ĐK:\left\{{}\begin{matrix}x\ne-1\\x\ne0\end{matrix}\right.\\ \Leftrightarrow x\left(x+3\right)+\left(x-3\right)\left(x+1\right)=2.x.\left(x+1\right)\\ \Leftrightarrow x^2+3x+x^2-3x+x-3=2x^2+2x\\ \Leftrightarrow2x^2+x-3=2x^2+2x\\ \Leftrightarrow x-2x=3\\ \Leftrightarrow-x=3\\ \Leftrightarrow x=-3\left(t/m\right)\)
\(a,5x-10=0\Leftrightarrow5x=10\Leftrightarrow x=2\)
\(b,7x-6=2x+9\Leftrightarrow7x-2x=9+6\Leftrightarrow5x=14\Leftrightarrow x=\dfrac{14}{5}\)
\(c,\left(x+5\right)\left(4x-9\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\4x-9=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=\dfrac{9}{4}\end{matrix}\right.\)
\(d,\dfrac{x+3}{x+1}+\dfrac{x-3}{x}=2\left(dkxd:x\ne0;-1\right)\)
\(\Leftrightarrow x\left(x+3\right)+\left(x+1\right)\left(x-3\right)-2x\left(x+1\right)=0\)
\(\Leftrightarrow x^2+3x-3x+x^2+x-3-2x^2-2x=0\)
\(\Leftrightarrow-x-3=0\)
\(\Leftrightarrow x=-3\) \(\left(tm\right)\)