Three guys are standing in a row, facing a solid, high wall. Guy A is 10 m from the wall, B is 20 m away from the wall, and C is 30 m away from it. Guy B shouts. Will any other guy be able to hear an echo of Guy B’s shout?

Only guy B and C will be able to hear the echo but guy A  will not be able to hear the echo

Explanation:

Given that:

Guy A  = 10 m away from the wall

Guy B = 20 m away from the wall

Guy C = 30 m away from the wall

At standard Temperature of 20 °C, velocity of sound in dry air ≅ 343 m/s. As such, if there is a reflecting object that produces an echo, it mustn't be more than 17.2 m from where the sound is originating from. As the sound is coming from guy B who is 20 m away, only Guy B and C who are above 17.2 m will only perceive the  echo.

because it says use -2,0,and 2 for x, we can plug those numbers into the equation. y/4=3/4(-2)+2   y/4= -1 1/2 +2 now to get x by itself, we can multiply each side by 4. y=-6+8 which equals y=2 when x=-2. now you can do the same thing with 0 and 2 as x. you get y=8 when x=0 and y=14 when x=2.

x   |   y

-2 |   2

0   |   8

2   |   14

the answer would be   dignified - apex