The key to simplifying this expression is to first factor the numerator. When factoring, always look for the greatest common factor first...the largest thing that divides evenly into the other terms...in this case it would be

We get:

The can be cancelled because it is a FACTOR of both the numerator (top) and denominator (bottom) of the fraction.  Notice that is really equal to 1 so "cancelling"  means you were really multiplying by 1 and have reduced that part of the fraction.

The simplified result is:

      It is not necessary to keep the parentheses.

The most common MISTAKE in these problems is to cancel terms instead of factors.  For example, some people might be tempted to cancel the 8s in the original problem.  The 8s are part of terms.  In the numerator, 8 is not a factor of both of those terms so you CANNOT cancel it.

Note:

which is what you would get if you cancelled the xs.  Pick any two numbers and plug them in for x and y to prove to yourself both sides are not equal. The only time it would work would be if you let x =1.