Answer:
1
Step-by-step explanation:
1*1=1
thats it tbh
f(6) = 10, f(10) = 30, f(20) = 80
Plug in the values into the equation and compute. 5*6 - 20 = 10, 5*10 - 20 = 30, 5*20 - 20 = 80.