The midpoint (x, y) and the end point
(22, y2) are known. Find
(21, y1) using the midpoint formula.

(21, y1) = (x + 22, y + y2)
(21, yı) = (2x – 22, 2y - y2)
(21, y1) = (x – 22, y - y2)
(21, yı) = (2x + 22,2y + y2)

e

step-by-step explanation:

an equation by definition has to have two or more variables (x and 2 in this case)

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

it should be a.

hope it