Let f(x)=2x+3f(2h+1)
f(x) = 2x + 3f(2h + 1) = 2(2h + 1) + 3f(2h + 1) = 2(2h) + 2(1) + 3f(2h + 1) = 4h + 2 + 3f(2h + 1) = 4h + 5
