For the function $(R$ : the set of real numbers$)$ below, determine whether

a$)$ It is bijection or not $($justify your answer or show all the steps to get the full points$).$

b$)$ If it is bijection, then find a formula for the inverse function.

$($Justify or show all the steps for your answer to get the full points, as just writing the formula is not enough for any points$).$

$f$:$RR$::$f(x)=3x+5$