<em>First you combine like terms</em>. Here we have t<em>hree terms</em>, <em>two</em> of which <em>we can combine</em>. Positive five plus positive five is 10. But, we cannot forget about our <em>remaining term</em>, '+x' so we simply have '10' and '(plus)x' put them together and we achieve 10+x or 10+?
