Question 988767
You NEED to know what kind of regular polygon, specifically HOW MANY SIDES, otherwise you can NOT find the perimeter.


The polygon being "regular", means the sides are congruent  (same or equal measures), so at least you can say  {{{5(x+2)=7x+4}}}, and if the solution to this is reasonable, then you can find just the size of a side.


{{{5x+10=7x+4}}}
{{{10=2x+4}}}
{{{6=2x}}}
{{{x=3}}}


You only know from this that each side length is {{{5(3+2)=7*3+4}}}
{{{highlight(25)}}}------how many units is one side.