Angle CFE and angle FCD are alternate interior angles (saw this question before that included the transversal as well)
Sum of all exterior angles = 360
360 divided by s
s = sides
360 divided by 10 = 36
C.360
It is distributive property. you would need to distribute the 8 onto the x and 7, making it 8x+56
The answer is about $1.96