Next time include the entire question please; we're guessing here.
XZA and ZXL are alternate interior angles assuming we're told XL and AZ are parallel. Alternate means on opposite sides of the transversal; interior means between the parallel lines.
If that 123 degrees is indicating angle ZXL it also is the value for angle XZA because alternate interior angles are congruent.
Answer: angle XZA = 123°