Hello i need help with this question

For which pairs of functions is (f•g)(x)=12x? f(x)=3-4x and g(x)=16x-3 f(x)=6x2 and g(x)= 2/x f(x)= and g(x) = 144x f(x)=4x and g(x) =3x

Factor the following polynomial completely 514 + 2013 - 1052 oa. 5121 + 3)( - ) ob. 51%(1 - 3)(1 + 7) oc. 5198 - 3)(x + 7) od 51%(+ 3)(x - 7)

David pays a 20% income tax on his $2,100 salary. how many dollars is the tax? show work