We can represent the limit above by a combination of two limits for the rational functions involved.
limx→2(x−21−x2−44)=limx→2x−21−limx→2x2−44
But from close inspection, we can infer that both diverge when x approaches 2, so we can combine them into a single rational function and find the limit.
limx→2(x−21−x2−44)
limx→2x2−4x−2
limx→2(x−2)(x+2)x−2
limx→2x+21=2+21=41