Math 110 Course Resources - Exponential \& Logarithmic Functions Course Packet on laws of exponential and logarithmic functions Use the laws of logarithms to write each expression as a single logarithm. (a) 5log(x)4log(y)= X (b) 21ln(x)7ln(y)3ln(2)= (c) 71ln(x+5)751[ln(x20)ln(x2+4)5]=.