Answer: Because division is the inverse of multiplication.
Explanation:
By multiplying the equation 2x=20 by 1/2 you will be able to eliminate the x variable,
For example,
1/2 * 2x = 20*1/2
x= 10
The same way if you divide both sides of the equation 2x=20 by 2 you will be able to to eliminate the x variable.
For example
2x = 20 Divide both sides by 2
x= 10
As you can see 2 is the division inverse of 1/2.