Answer:
x=40
Step-by-step explanation:
Sum of all angles in a quadrilateral is 360. Subtract 80 from 360. Now you have 280. Now you have to add all the x values together to see that 7x=280. Then you must simplify by dividing 7 on both sides, resulting in x=40
Equation if you wanna work it out and solve:
360=80+7x
