Step-by-step explanation:
Set-builder notation is a notation for describing a set by indicating the properties that its members must satisfy.
C={2,4,6,8}
C={2×1,2×2,2×3,2×4}
thus set builder form is:
{x:x=2n,n∈N} and this set is also call even number set in description mathod
The equation (form) is: 
The solution of the equation is: 
Explanation:
First, let's call the number we are going to solve for "x".
Then two thirds of this number can be written as:

Then "plus 4" means add 4 we get:

"is 7" means that the above expression is equal to 7 (as follows):

The solution of the above equation is:

Answer:
For example, the years 1600, 2000, and 2400 are century leap years since those numbers are divisible by 400, while 1700, 1800, 1900, 2100, 2200, and 2300 are common years despite being divisible by 4.
Step-by-step explanation: