Answer:
19) x = 15
20) x = 16
21) Never, because supplementary means 2 angles that add up to 180 degrees, and obtuse angles are angles that are more than 90 degrees.
22) Never, because complementary means 2 angles that form a 90 degree angle, but vertical angles are across from each other and will never meet, otherwise it's not called vertical angles.
Explanation:
19) Supplementary angle = 2 angles that add up to 180 degrees. Therefore, the equation is 45+9x = 180. To solve for x, subtract 45 from 180, which equal to 135. Then, divide 135 by 9, which equal to 15.
20)Complementary angle = 2 angles that add up to 90 degrees. Therefore, the equation is 4x+26 = 90. To solve for x, subtract 26 from 90, which equal to 64. Then, devide 64 by 4, which equal to 16.
I can't really do #23, but I hope those above helps^