Step-by-step explanation: Knowing that this is on a straight line, which is 180°, you can assume that both angles add up to 180°. You can turn this into an agebraic equation by saying that (10x-20)°+(6x+8)° = 180°. by simplifying, you get 16x-12 = 180. Adding 12 to both sides yields 16x = 192. To finish the equation, you divide both sides by 16; completing to x=12.
