To solve this problem, we need to determine the value of x, which represents the number of students who will not be coming to class on Monday.
We know that Lucas makes 4 pieces of chocolate candy for each of his students on Monday. Therefore, the total number of pieces of chocolate candy made last Monday is equal to 4 times the number of students.
Let's set up the equation based on the given information:
Total number of pieces of chocolate candy made last Monday = Number of students * 4
40 = Number of students * 4
To solve for the number of students, we divide both sides of the equation by 4:
Number of students = 40 / 4
Number of students = 10
Therefore, there are 10 students in Lucas' class.
Now, let's use the second piece of information to find the value of x.
This upcoming Monday, Lucas will make 28 pieces of chocolate candy. We know that this is equal to 4 pieces of chocolate candy for each student minus x (the number of students who will not be coming to class).
Let's set up the equation:
28 = (Number of students - x) * 4
Substituting the value of the number of students:
28 = (10 - x) * 4
To solve for x, we divide both sides of the equation by 4:
28 / 4 = (10 - x) * 4 / 4
7 = 10 - x
To isolate x, we subtract 10 from both sides of the equation:
7 - 10 = -x
-3 = -x
Finally, to solve for x, we multiply both sides of the equation by -1:
-3 * -1 = -x * -1
3 = x
The value of x is 3. Therefore, 3 students will not be coming to class on Monday.
#### 3
The answer is: 3
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Every week, Lucas makes 4 pieces of chocolate candy for each of his students on Monday. He made 40 pieces of chocolate candy last Monday. This upcoming Monday, x of Lucas' students will not be coming to class. Lucas will make 28 pieces of chocolate candy for his class on Monday. What is the value of unknown variable x?

### Answer:
