m∠136 & ∠x are alternating interior angles, which definition states that the two angles have the same measurement and are congruent. This means that m∠x is also 136°.
Because the 136 degree angle and angle X would be vertical angles if one was slid down the line(forgot the name, sorry), they add to equal 180 degrees. So because one of them is known as 136 degrees, you know angle x is 44 degrees.
