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Note that on putting $x=\\var{a}$ into $\\displaystyle \\simplify{(x + { -a}) / (x ^ 2 + { -a -b} * x + {a * b}) }$ we get a $0/0$ case and so we have to do more work.

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You can factorise $\\simplify{x ^ 2 + { -a -b} * x + {a * b}}$ and then see what happens. 

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Find the limit of the following function.

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$\\displaystyle \\simplify{Limit((x + { -a}) / (x ^ 2 + { -a -b} * x + {a * b}),x,{a}) }=\\;$[[0]] (input as a fraction or as an integer).

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Input as a fraction or an integer.

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