Hey there! :) To find the value of "x," we have to first find the other angles. Remember that every straight line adds up to 180°! :)
This is a fairly easy question, as you simply just ignore the inside triangles, as we are already given the angles.
Look at the bottom angles of the whole triangle - all you need to do is add 55° with 65°, then subtract the answer from 180°. Why? Simply because all triangles, added up, equal 180°.
So : 55° + 65° = 120°
180° - 120° = 60°
Therefore, x = 60°
~hope I helped!~