Question

Consider the following sets.

U = {ordered pairs on a coordinate plane}
A = {ordered pair solutions to y = x}
B = {ordered pair solutions to y = 2x}

Which ordered pair satisfies A ∩ B?

(0, 0)
(1, 1)
(1, 2)
(2, 1)

Answer 1

A ∩ B are points with y = x and y = 2x, so x = 2x ⇒ x = 0, hence y = 0. The intersection is {(0, 0)}, so (0, 0).