This is the most common, and probably the most damaging myth bout SEO. The notion that you have have to have the exact URL that people are searching for, or that multiple URLs will drive up your SEO is simply outdated and wrong. Google largely ignores URLs because of the dot-com boom, and knows that domains are bought and sold and are largely irrelevant to a given search. Multiple URLs are ‘grey-hat’, that is a questionable SEO practice, and Google will see right through it and will often penalize it as spam- which will keep your ranking down forever.