Question

f(x+2)=2(2f(x)+1), f(2)=4, f(6)=?

Answer 1

$f(2)=4\\f(x+2)=2cdot (2cdot f(x)+1)\\a); ; x=2; ,; f(2+2)=2cdot (2cdot f(2)+1)\\f(4)=2cdot (2cdot 4+1)\\f(4)=18; ,\\b); ; x=4; ,; f(4+2)=2cdot (2cdot f(4)+1)\\f(6)=2cdot (2cdot 18+1)\\f(6)=74$