19.6 divided by 9 pls no long numbers just do it simply

If you have 12 feet of string and you cut it into equal length of 5 inches each how much string will be left

Which expressions equal 9 when x=4 and y=1/3 a. x2+6y b. 2x + 3y c. y2-21x d. 5 (x/2) -3y e. 3x-9y

Show all work to identify the discontinuity and zero of the function f of x equals 6 x over quantity x squared minus 36