Answer :
(f-g)(x) is a shorthand way of saying that you need to get the difference of the two functions: f(x) and g(x). so essentially,
(f-g)(x) = f(x) - g(x)
= 5x+2 - (-3x+4)
= 8x-2
(f/g)(-2) = f(-2)/g(-2)
= -4/5 or -0.8
Hope this helps.