Answer:
f(1) = 12
Step-by-step explanation:
We know that f(x)=f(x-1)+2x+1
We are told that f(2) = 17
Use the first equation to calculate f(1). Since f(2) is known and f(x-1) will become f(1) after f(2-1) is simplified to f(1).
17 = f(2-1)+2*2+1
f(2-1) = 17 - 5
f(1) = 12