9!-4! (5!) How do i solve?

To simply the expression, we should remember an! in math represents every number (til 1) before that one multiplied or "the product of the integers from 1 to n"

So now that we have the definitions we can simplify by finding the values of each:

(9x8x7x6x5x4x3x2x1) - (4x3x2x1) (5x4x3x2x1)

After simplifying this will equal to 3600