Answer:
2
Step-by-step explanation:
First off, the slope of f(x) is -4. It is in the form y=mx+b and m=-4.
For g(x), the slope can be calculated from any two points given. I willuse (1,9) and (3,21) because I like positive numbers. So, slope is rise over run and it is calculated from (y1-y0)/(x1-x0) This gives me (21-9)/(3-1) which is equal to 6. So adding the two slopes: 6+ (-4)=2
