Ineed on one of my math questions. it would be most to get the answer as well as an explanation on how to do these types of problems. you in advance.

This is a very interesting problem.  What makes it so interesting is that
there's so little actual math to it.  The only big Math thing you need to know
in order to work with this question is the definition of "perimeter".

  "Perimeter" means

                 "the distance all the way around the edge of something".

The problem GIVES you the length of all the sides of both triangles.
To find the perimeter of one triangle, just take the lengths of its three
sides and addum up.

The perimeter of the blue one is    (7x+7) + (5x-4) + (4x+2)  .
That's it !  That's the perimeter.  Of course, they want you to write
it in simplest form, so you have to clean it up.  Remove all of the
parentheses, add up all the 'x's, and add up all the plain numbers,
and you'll have a short, pretty expression.

Then do the same thing for the red one, and get its perimeter.

In part-b, they want you to find the difference between the two perimeters.
No problem.  Just write  (the blue perimeter) minus (the red perimeter),
and simplify THAT expression.

Now they want the actual perimeters when 'x' is 3.
No big deal.  Just take each separate perimeter, write '3' in place of 'x',
and find the number that the expression becomes.

Just now, looking at the picture without writing anything down,
I got  53  for the blue one and  17  for the red one.
I could easily be wrong, so you definitely have to work them
out for yourself.