The fact that there are two length sides and two width sides.
Answer: See below
Explanation:
8x + 14 = 10x - 10 (alt. exterior angle)
8x - 10x = -10 - 14
-2x = -24
x = -24/-2
x = 12
Now plug x = 12 in 10x - 10 to find the angle:
10(12) - 10 = 120 - 10 = 110 degree
The answer is -80, i have done all the math and -80 is the answer