Question

If f(n)=f(n-1)+8 and f(1)=7, what is f(50)

Answer 1

$f(n)=f(n-1)+8=f(n-2)+2\times8=f(n-3)+3\times8=\cdots=f(1)+(n-1)\times8$

Since $f(1)=7$, you have

$f(50)=f(1)+(50-1)\times8=399$