4^(2x+1)=1/6 what is x

Taking the logarithm of both sides with base 4:

(2x+1)log4 = log(1/6)
2x+1 = log(1/6) / log4
2x+1 ≈ -1.7712
2x ≈ -2.7712
x ≈ -1.3856
Therefore, x ≈ -1.3856.