What is used to show relationship between two variable?

Answer 1

In mathematics? This is what's called a relation.

For example, the relation y=4x shows that for any given x value, the value of y is four times as great.

If y is equal to 8 and the relationship between y and x can be shown by the relation y is equal to four times x, x must equal 8 divided by four. Eight divided by four is 2, therefore x is equal to 2.

If x is equal to 6 and the relation ship between y and x can be shown by the relation y is equal to four times x, y must equal 6 multiplied by four. Six multiplied by four is 24, therefor y is equal to 24.