The answer is A, not sure about the expression though. Sorry
Answer:

Step-by-step explanation:
We know that

Given :

So 4 is the opposite side of theta.

We use the Pythagorean theorem to find for the adjacent side.
Answer:
It is linear because the ratio of the change in the final cost compared to the rate of change in the price tag is constant.
Answer:
X=6, Y=-1
Solved using substitution