# What is the slope of any line perpendicular to the line passing through #(-9,8)# and #(3,-3)#?

##### 1 Answer

12/11

#### Explanation:

The coordinates given can be used to determine the gradient.

In standard form the equation of a straight line is:

Where

The trick is, that the gradient of the line perpendicular to the first is:

So all you need to do is find the gradient of the first line then the other is just a matter of turning the first one 'upside down' and multiplying it by (-1)

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let

Let

Then the gradient is:

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So for the perpendicular line its gradient is: