Explanation:
To solave this, you need to learn/know that :
3x +127 and 23 are supplementary
so
3x+127 + 23 = 180
3x = 30
x = 10 units
Another way :
Angle G = 1/2 * (large intercepted arc - small intercepted arc )
23 = 1/2 ( (360 - (3x+127) ) - (3x-127) )
23 = 1/2 ( 360 -3x - 127 - 3x - 127)
23 = 1/2 ( 106 -6x )
23 = 53 - 3x
x = 10 units