Hi, log4[x]+log4[x-63]=3 log4[x(x-63)] = 3 4^3 = x(x-63) x^2 -63x - 64 = 0 factoring: (x-64)(x+1) = 0 (x-64)= 0 x = 64 (x+1) = 0 x = -1 Extraneous solution 64 is the real solutions for x