Somebody help me with the first two please

If you double the input of a function and it results in half the output, and if you triple the input and it results in a third of the output, what can be guessed about the function? check all that apply.

Determine the intercepts of the line that passes through the following points. (15,-3)(15,−3) (20,-5)(20,−5) (25,-7)(25,−7)

Find a third-degree polynomial equation with rational coefficients that has roots -2 and 6+i