Answer:
x = 9 , z = 79
Step-by-step explanation:
(12x - 7) and (5x + 56) are vertically opposite angles and are congruent, so
12x - 7 = 5x + 56 ( subtract 5x from both sides )
7x - 7 = 56 ( add 7 to both sides )
7x = 63 ( divide both sides by 7 )
x = 9
Then
5x + 56 = 5(9) + 56 = 45 + 56 = 101
z and (5x + 56) are adjacent angles on a straight line and sum to 180°, that is
z + 101 = 180 ( subtract 101 from both sides )
z = 79
