f ( 2 ) = 2 × f ( 2 - 1 ) + 1
f ( 2 ) = 2 × f ( 1 ) + 1
f ( 2 ) = 2 × ( - 3 ) + 1
f ( 2 ) = - 6 + 1
f ( 2 ) = - 5
4.5m questions
5.9m answers