if line m is parallel to line n and is cut by a transversal and angle 4 =3x - 20 and angle 5 = x + 40, what is the value of x?

Answer 1

Where are the angles 4 and 5 in question? Are their values 4 and 5 degrees? Or is "Angle 4 and Angle 5" just the way they are labeled?

The four inside angles formed when parallel lines are cut by a traversal are supplementary pairs.

Thus, perhaps,
(3x -20) + (x +40) = 180
4x = 160
x = 40