<s>[INST] Solve quadratic fraction I would like to simplify the fraction
$$\frac{x^2-2x}{x^2+x-6}$$
I know from Mathematica that it should equal $\frac3{3x}$ but how do I get there? 
 [/INST] $x^2+x-6 = (x-2)(x+3)\rightarrow \frac{x(x-2)}{(x+3)(x-2)}=\frac{x}{x+3}$, so your result is incorrect, as the next counterexample shows: 
$x=1; \frac{x^2-2x}{x^2+x-6}=\frac{1}{4}\neq 1=\frac{3}{3x}$
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