Mr. Rodriguez bought 6 liters of diet soda. His two sons will drink the same amount each day and finish the diet soda in 4 days. Which expression shows how much they will drink each day? B​

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?

Solve the system of equations. y= 2x y= x^2 - 15

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=