Thank you for the opportunity to help you with your question!
27x/x is about simplifying expressions. To do so here, you cancel out the x in the numerator (top number) with the x in the denominator (bottom number). Getting rid of x/x is the same thing as dividing by 1, since any number divided by itself is 1. And since dividing by 1 doesn't change a number, that means that you're just left with 27 as your answer. To show your work, you can cross out the x's to show canceling out, or simply write that you are canceling the x's.
Please let me know if you need any clarification. I'm always happy to answer your questions.