Question

A and B?

Answer 1

A is good, B is not

if x = 0, then E(x) = ?

Answer 2

E(0)

Answer 3

good, and if E(x) = 10x - 30, then what is E(0) = ?

Answer 4

3?

Answer 5

replace "x" with 0 and calculate 10*x - 30

Answer 6

oh -30

Answer 7

because 10*0 is 0

Answer 8

and then -30 is -30

Answer 9

good, so she loses 30 dollars if she doesn't knock at all

so A & D