Answer:
x = 25
Step-by-step explanation:
The interior angle adjacent to the 123° angle is supplementary to it.
Its measure is 180° - 123° = 57°
The sum of the measures of the interior angles of a polygon is
(n - 2)180° = (4 - 2)180° = 2(180°) = 360°
3x + 7 + 96 + 5x + 57 = 360
8x + 160 = 360
8x = 200
x = 25
