I am assuming that the figures of 26 and 30 are angles in degrees.
Congruent triangles have exactly the same sides and angles.
I assume AB is of one triangle.
XY and YZ are of the other.
I also assume that AB corresponds to XZ.
As you probably know, all angles of a triangle total 180 degrees.
Let's combine like terms...
Let's combine like terms by subtracting 58 from both sides...
Let's divide both sides by 4...
Let's check our work...