Answer:
x = 70
Step-by-step explanation:
Properties of a parallelogram.
1). Pair of opposite sides of a parallelogram are equal in measure and parallel to each other.
2). Opposite angles of a parallelogram are equal in measure.
3).Adjacent angles of a parallelogram are supplementary.
By the second property,
(2x - 30) = (x + 40)
2x - x = 30 + 40
x = 70