Question

50 POINTS! PLEASE HELP!!! APEX ALGEBRA!!

Answer 1

Plug in the values to check the answer.

Assume 10 doors are knocked: 
E(10) = 20(10)-50 = 200-50 = 150 

Assume 11 doors (1 more door) is knocked: 
E(11) = 20(11)-50 = 220-50 = 170 

The increase from 1 door is $20.

Saying that, The answer is B.

Answer 2

For the answer to the question above, 
since the only variable used to determine earnings is the number of doors knocked, you can eliminate options 1 and 3 as they are based on the number of books sold, which is not a part of the equation. 

That leaves the only options being the increase of $20 or $50 for each door knocked. As the x value we multiply by 20, the correct answer is #2, her earnings will increase by $20 for each door knocked. 

You can also check this by plugging in values: 

Assume 10 doors are knocked: 
E(10) = 20(10)-50 = 200-50 = 150 

Assume 11 doors (1 more door) is knocked: 
E(11) = 20(11)-50 = 220-50 = 170 

The increase from 1 door is $20. the answer is B