cannot seem to come up with fractions that will cancel each other out. Have always had problem understanding how to multiply fractions

(21/12x - 1/12) = 0

(22/33x - 36/33) = 0

how do I figure out the x

we are learning to solve equactions by factoring using the Principle of zero products .... but my instructor never did any fractions for an example. All I understand is the there are two different values for X ---