Question 247085

2X^2-32/x-4 
.
Factoring a 2 from the numerator:
[2(X^2-16)]/x-4 
[2(X+4)(X-4)]/x-4 
Canceling x-4:
2(X+4)
2X+8
.
This will NOT be true if X=4 -- notice the denominator goes to zero making it undefined.