f(x)= 5 - x and g(x)= 3x + 7. Simplify f(2x) + g(x-1) (2018 past paper question)

If f(x)= 5 - x then f(2x)= 5 - 2x If g(x)= 3x + 7 then g(x-1)= 3(x-1) +7 = 3x - 3 + 7 = 3x +4
So f(2x) + g(x-1) = 5 - 2x + 3x + 4 = 9 + x