Introduction
To find the rational numbers whose numerator is (-7 ×2) and denominator is (21-?), we need to understand what rational numbers are and how to simplify fractions.

What are rational numbers?
Rational numbers are numbers that can be expressed as a ratio of two integers. They can be written in the form of p/q, where p and q are integers and q is not equal to zero.

Simplifying Fractions
To simplify fractions, we need to find the greatest common divisor (GCD) of the numerator and denominator and divide both by it. This will give us the simplified fraction.

Steps to find rational numbers with numerator (-7 ×2) and denominator (21-?)
1. We know that the numerator is (-7 ×2) = -14.
2. We need to find the denominator, which is (21-?).
3. We can simplify the expression (21-?) by factoring out the greatest common divisor.
4. The GCD of 21 and ? is 3, since both 21 and ? are divisible by 3.
5. We can write (21-?) as 3(7-?), since 21/3 = 7 and ?/3 = (7-?/3).
6. Now we can write the rational number as (-14/3)*(1/(7-?)).

List of rational numbers
The rational numbers whose numerator is (-7 ×2) and denominator is (21-?) are:
- (-14/3)*(1/(7-?))
- (14/3)*(1/(? - 7))

Explanation
We can simplify the denominator by factoring out the GCD, which is 3. This will give us the expression 3(7-?). We can then write the rational number as (-14/3)*(1/(7-?)). We can also write this as (14/3)*(1/(? - 7)). These are the only two possible rational numbers that can be formed using the given conditions.

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