When two constants $a , b$ satisfy $\lim _ { x \rightarrow 2 } \frac { x ^ { 2 } - ( a + 2 ) x + 2 a } { x ^ { 2 } - b } = 3$, what is the value of $a + b$? [2 points] (1) $- 6$ (2) $- 4$ (3) $- 2$ (4) 0 (5) 2
When two constants $a , b$ satisfy $\lim _ { x \rightarrow 2 } \frac { x ^ { 2 } - ( a + 2 ) x + 2 a } { x ^ { 2 } - b } = 3$, what is the value of $a + b$? [2 points]\\
(1) $- 6$\\
(2) $- 4$\\
(3) $- 2$\\
(4) 0\\
(5) 2