Answer:
I think i gave u answer for 21 and 23 but ill give ya again :)
21.) x = 0
22.) x = 8
23.) x = 0
24.) x = 12
Explanation:
21.) x + 12 = 12
=> x = 0
22.) x - 1 = 7
=> x = 8
23.) 12 + 2x = x + 12
=> 12 + x = 12
=> x = 0
24.) 2x - 14 = 10
=> 2x = 24
=> x = 12
(All of these equations are set equal to their opposite side on the same figure since both the sides are parallel and congruent)
Hope this helps!