# What is the equation of the line passing through #(21,4)# and #(18,-2)#?

##### 1 Answer

May 14, 2018

#### Explanation:

The equation of a straight line is

(the symbol for delta is wrong. It is actually a triangle. Delta means "change in".)

So in our case:

You can then substitute 2 into the equation:

You can then find out what c substituting one of the co-ordinates in.

If you take away 42 from both sides

So the answer is