Answer:
A. 4
Explanation:
First off, x + 3 needs to equal 2x - 1, since the parallel sides of the parallelogram have the same length. Let's check A first, which says x = 4.
I) Substitute equations:
x + 3 = 2x - 1
4 + 3 = 2(4) - 1
II) Solve:
4 + 3 = 2(4) - 1
7 = 2(4) - 1
7 = 8 - 1
7 = 7
x = 4