2^(2x+1)-2^(x+2)-2^x <=3

(2^(2x)) *2 - (2^x) *(2^2) -(2^x) -3 <=0

2*(2^(2x)) -5*(2^x) -3 <=0|t=2^x

2t^2-5t-3<=0

D=49

t1=3, t2=-0,5

2(t-3)(t+0,5)<=0

     +                  -                +

----------[-0,5]---------[3]--------

             -0,5<= t <=3

             -0,5<= 2^x <=3, но  2^x>0

                  0< 2^x <=3

                  x<=log_2{3}