Answer :
[tex]\bf \cfrac{1}{x^2+3x-10}-\cfrac{6}{x-2}\implies \cfrac{1}{(x+5)(x-2)}-\cfrac{6}{x-2}\impliedby \stackrel{LCD}{(x+5)(x-2)}
\\\\\\
\cfrac{(x-2)~~-~~(x+5)6}{(x+5)(x-2)}\implies \cfrac{x-2-6x-30}{(x+5)(x-2)}\implies
\cfrac{-7x-32}{(x+5)(x-2)}[/tex]