Which equation shows a proportional relationship between x and y? A. y=-3x-2
B. y=9
C. y=3x+1
D. y=4x

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?

What is x3+3x2−16x−48 divided by x−1?

    choose the correct definition for  extremo.  a.  end      b.  extra      c.  extract      d.  eventual