Answer:
x = 25
Step-by-step explanation:
Since the triangles are congruent then corresponding angles are congruent.
That is ∠ D and ∠ B are corresponding angles and congruent, thus
4x - 20 = 2x + 30 ( subtract 2x from both sides )
2x - 20 = 30 ( add 20 to both sides )
2x = 50 ( divide both sides by 2 )
x = 25
