Answer: 4n - 7 = 21, n = 7
Explanation:
A difference indicates subtraction of two terms. Four times a number indicates that a number of any value has to be multiplied by 4.
Hence, the equation that is represented by the question is

We can also solve this equation (i.e., find the value of x that makes this equation true).
Adding 7 to both sides, we get

Since the -7 and 7 add to 0, the equation becomes

To get x by itself, we can divide both sides by 4, making the equation

Hence, x must be 7 to make the equation true, or 7 is a solution to the equation.