The given angle of 105 and angle z are consecutive interior angles and need to equal 180 degrees.
Z = 180-105 = 75 degrees
Angle z and angle c are vertical angles and are identical so angle x also equals 75 degrees
Angle y and 105 are supplementary angles and when added equal 180
Angle y is 180-105 = 75
X, y and z are all 75 degrees