The problem
Click to see the original problem
I got the same result on my own, but my professor says the denominator is in correct.
Answer provided by our tutors
The lowest common denominator or least common denominator (abbreviated LCD) is the lowest common multiple of the denominators of a set of fractions.
In your case the fractions are
So, the least common denominator for 'x-6' and 'x' is '(x-6)x'