Answer:
21.) x = 0
23.) x = 0
Explanation:
21.)
We know that Sides AD and BC are parallel to each other, so they are congruent as well, thus we can say:
x + 12 = 12
=> Now just subtract 12 on each side of "="
x = 0
23.)
We know that sides SV and TU are parallel which makes them congruent, hence;
12 + 2x = x + 12
=> First subtract x from each side,
12 + x = 12
=> Lastly subtract 12 on each side:
x = 0
Hope this helps!