Tom worked 4 hours on Monday and 52 hours on Tuesday. How many hours total did he work?
11
9
hours
20
11
B 10
hours
24
11
9
24
hours
11
D 10 hours
20


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?

Consider the function f(x)=−2/3x+5 . what is f(1/2) ? enter your answer, as a simplified fraction, in the box. f(1/2)=

Astudent simplified a rational expression as shown.