Zero is the only number that has zero as a factor, both sides where equal to zero, the only number that you could factor out a zero from is zero since it is the only number that has zero as a factor. Did I mention that the only number that has zero as a factor is zero? Do you know of any other numbers that can be a product of a factor of zero?

Lets try 1, does 1 have a factor of zero in it? Can we factor out a zero out of 1? Lets see 1/0 = undefined darn didn't work. Lets try 2, does 2 have a factor of zero? 2/0 = undefined , How about 3 anything we could multiple by zero in order to get 3? 3/0= undefined, oh well I give up, have a nice day.