To multiply fractions, all you have to do is multiply the numerators and denominators and simplify the result. To divide fractions, you simply have to flip the numerator and denominator of one of the fractions, multiply the result by the other fraction, and simplify.
subtract 4x from each side first. 8x-4x+60=4x-4x+100 which equals 4x+60=100. Then subtract 60 from each side. 4x+60-60=100-60 which equals 4x=40. Then divide both side by 4 which equals x=10.