Problem Solve the exponential equation 4x + 4x + 1 = 40. Solution 4x + 4x + 1 = 40 => 2(4x) = 39 => 4x = 39/2 Using the laws of logarithm x log 4 = log 39 – log 2 x = (log 39 – log 2)/log 4 x = (1.59106 – 0.30103)/0.60206 x = 2.14206