What are the factors of 6tu

Depending on the value of 't' and 'u', the numerical value of that expression
could have almost anything for factors. 

For example, if  't' happens to be 3 and 'u' happens to be 10, then  6tu = 180,
and the factors of  6tu  are

   1,   2,   3,  4,  5,  6,  9,  10,  12,  15,  18,  20,  30,  36,  45,  60,  90, and  180.

But that would only be temporary ... only as long as  t=3  and  u=10. 

The only factors you can always count on, that don't depend on the values
of  't'  and  'u', are

           1,  6,  t,  u,  6t,  6u,  tu,  and  6tu .

the formula of a slope:

from a table we have

substitute:

the slope of f(x) is -1.

the graph of funcfion g(x) is a horizontal line. the slope of a horizontal line is equal 0. therefore the slope of g(x) is 0.

-1 < 0

answer: the function g(x) has the greatest slope.