How do you identify the opposite and the absolute value of a rational number

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?

7(x - 2) = 3(x + 4) solve the following equation. then enter your answer in the space provided using mixed number format.

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15