Since you have y alone on one side of the equation......
Use substitution and plug in 1/2x-4 for y in the other equation.

Distribute

Combine like terms

Add 8 to both sides

Divide by 4
and 
Plug this value in for x

Simplify

Multiply everything by 8 and simplify

Divide.....

Your answers are:

(X+4)(X-4) is the LCD because you just have to look at the denominators and see what factors or values are not already part of your LCD.
Answer: Its the 2nd and 4th
Step-by-step explanation:
i am sorry i know its not gonna help you now but its for others!
If events E1 and E2 are mutually exclusive, it means that it is impossible for them to happen together. The probability of the occurrence of one or more of these events is the sum of their individual probabilities. The answer for this item would be,
P(E) = P(E1) + P(E2) + ...