Question

What equal x in this triangle

Answer 1

The answer to the question is x=32. 

Answer 2

The sum of the alternate interior angles is equal to the angle given to you there. So basically, the sum of the angles INSIDE the triangle that aren't next to the outside angle are equal to that outside angle's measure.
You already know that one of the angles is a right angle, which is equal to 90 degrees, so subtract that from the outside angle to get the measure of x.
122-90=x
x=32