Answer:

Step-by-step explanation:
Given


Required
The cost of units used
First, calculate the number of units used.



Next, multiply the units used by the cost per units,
Since the cost per unit is not given, we assume that it is x.
So, the total cost is:



Answer:
The traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum. One plate holds an object of unknown mass (or weight), while known masses are added to the other plate until static equilibrium is achieved and the plates level off, which happens when the masses on the two plates are equal. The perfect scale rests at neutral. A
When you write it as an inequality you get x + 4 > 13
A=1
Here is a picture. Please notify me if I made an error!