Ans. 1 Angle E and angle F are corresponding angles.
Solution 2.
So,
angle E = angle F
=> x + 20 = 5x - 20
=> x + 20 + 20 = 5x
=> x + 40 = 5x
=> 40 = 5x - x
=> 40 = 4x
=> 40/4 = x
=> 10 = x
Solution 3.
E = x + 20
=> E = 10 + 20
=> E = 30
F = 5x - 20
=> F = 5(10) - 20
=> F = 50 - 20
=> F = 30
Again justified that they are equal ( besides answer 1).