Question

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

Answer 1

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