How do you subtract an interger from another interger from without using a number line or counters? give an example

Polynomial that can be factored as (3x-4)(3x+4)

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Acircle has a circumference of 7.850 units. what is its radius?