Answer:
x=10
Step-by-step explanation:
Since the two given expressions are alternate interior angles ( as a result of the parallel line, which are indicated by the arrows on the two lines going through the middle line, the transversal) you can set them equal to each other.
5x-10 = 3x+10
add 10 on both sides
5x = 3x + 20
subtract 3x on both sides
2x=20
divide by 2 on both sides
x=10
