Answer:
See below.
Step-by-step explanation:
Angle 3 and angle 7 are corresponding angles and corresponding angles are equal when the lines are parallel.
4x+12 = 80-x
Add x to each side.
4x+12+x = 80-x+x
5x+12=80
Subtract 12 from each side
5x+12-12 = 80-12
5x = 68
Divide each side by 5
5x/5 = 68/5
x = 13.6
Since 13.6 does not equal 15, the lines are not parallel.
(The angles are not equal).
