2 4
a + 3 a - 3
Factor the denominators. (The given denominators are already on their factored form so we'll just copy them).
a + 3 = a + 3
a - 3 = a - 3
Let's construct their LCD.
LCD = (a + 3)(a - 3)
Rewrite each rational expression with the LCD as denominator.
2 4 = 2 (a - 3) 4 (a + 3)
a + 3 a - 3 (a + 3)(a - 3) (a + 3)(a - 3)
We get 2(a - 3) and 4(a + 3) from dividing the LCD to their factored denominators then multiply them to their numerator.
(a + 3)(a - 3) = a - 3
a + 3
(a + 3)(a - 3) = a + 3
a - 3
Now do the indicated operation.
2 (a - 3) - 4 (a + 3) = 2 - 4
(a + 3)(a - 3) 1
= -2
1
= -2
That's it. Hope you understand it! :)
-KookEin
Note: It's not copied :)
