The easiest way to show you how to do this is by working out an example.

Sample:

Find the distance between (-2, and (-7,-5).

1) Find the distance between the x-coordinates. To do this, subtract one number from the other and then find its absolute value.

We have: |-2-(-7)| = |5| = 5.

2) Do likewise with the y-coordinates.

We have: |8-(-5)| = |13| = 13.

NOTE: It does NOT matter which way you subtract the numbers because the absolute value of the answer would be the same anyway.

3) Square BOTH your answers, add them and take the square root.

5^2 + 13^2 = 25 + 169 = 194.

Taking the square root of 194 and rounding to TWO decimal places, we get a distance of 13.93.

By the way, what you are actually doing is using the Pythagorean Theorem on an imaginary right triangle with the line joining the two lines being the hypotenuse.

The general formula for distance between two points is the following: sqrt(x^2 + y^2), where x and y are the change in x and y between the two points