8. In the figure, lines a and bare parallel. Select all the statements that are true.
b
1/2
(x-15)°/4
6/5
753
m21 = m25
mz3 = M24
m21 + m24 = 180°
m26 = 75°
m22 + m25 = 180°

Here is their argument. given the obtuse angle x, we make a quadrilateral abcd with ∠dab = x, and ∠abc = 90◦, and ad = bc. say the perpendicular bisector to dc meets the perpendicular bisector to ab at p. then pa = pb and pc = pd. so the triangles pad and pbc have equal sides and are congruent. thus ∠pad = ∠pbc. but pab is isosceles, hence ∠pab = ∠pba. subtracting, gives x = ∠pad−∠pab = ∠pbc −∠pba = 90◦. this is a preposterous conclusion – just where is the mistake in the "proof" and why does the argument break down there?

Aline has a slope of and a y-intercept of –2. what is the x-intercept of the line?

The measure of an angle is 117°. what is the measure of a supplementary angle?