Part a: find the lcm of 5 and 12. show your work. (3 points) part b: find the gcf of 72 and 81. show your work. (3 points) part c: using the gcf you found in part b, rewrite 72 + 81 as two factors. one factor is the gcf and the other is the sum of two numbers that do not have a common factor. show your work. (4 points)