how would you do this?

Write it out so you have lots of space. This particular problem has two terms. So, to find the GCF we need to find ALL the things that these terms have in common. I always like to start with the coefficients, but it's really up to you if you start with the variables or the coefficients. For simplicities sake, let's multiply those together and write it out again. Remember that if you have numbers in the same term, you can multiply them together and the expression remains the same.

From there, we want to find the greatest common factor between what is now two coefficients: one in each term. In other words, you want to find the biggest number that goes evenly into both coefficients. Once you find it, write it outside the parenthesis, and divide both terms by the number you pick. Rewrite your equation again so that you now have the expression, but with the greatest common factor of the coefficient outside the parenthesis.

Now,, lets look at the x's. For any variable, the one with the lowest power will be the greatest common factor. In this case, that is x^{2}. So, we are going to put the x^{2}^{ }as part of the GCF, outside the parenthesis. Now, lets write out what we have left in the main expression. To figure this out, we need to divide both terms by x^{2}

you should follow the same process for y and z. In the end, you will have your GCF on the outside of parenthesis, and rest of the expression inside them. To double check your work, look at the main expression and make sure that the two terms have nothing else in common. If this is true, good job! if not, just keep on factoring, multiplying the factors you pull out with the GCF, and dividing the main expression by the same.