Answer:

Step-by-step explanation:
Here, given:

Now, here to find the values of 
As we know: 
Now, substituting x = 4 in f(x):

Now, substituting x = 1/2 in g(x):

The inequality should be

The sign on the right is only a 'smaller than' sign because he spent less than 180.
On the left, assuming that even if Calvin took nobody (poor Calvin), we should assume that he at least went himself, hence he spent a minimum of $12.
Wade wants to have at least $55 left, so the sign will be ≤ (greater than or equal to 55) One sweater costs $12. You can use x to represent an unkown number of sweaters, so $12x. You are subtracting 12x by your budget of $175. When put together, the inequality is $175-$12x ≤ $55.
Now to solve. You want to get x alone so subtract 175. You must do this to both sides. Now you have -12x≤ -120. Divide both sides by -12 and your final answer is -120/-12 ≥ 10. (Notice the sign changes when you divide by a negative)
So Wade cannot buy more than 10 sweaters to have $55 left over. Phoo that was a workout. It can be difficult but once you get the hang of it it comes easy. If you need more help just ask :D
Models can be used to describe, extend, and make generalizations about certain mathematical situations.