- Equation of a straight line: y=mx+c
- Equation of a line given the gradient and point
- Distance between two points
- Mid-point of a line segment
- Equation of a parallel line
- Equation of a perpendicular bisector

In the first tutorial I introduce you to the equation y = mx + c and the meaning of m and c.

### Experiment with the Graph

Experiment with the graph below by changing the parameters to see how it affects the graph.

Common questions using y=mx+c

Finding the equation of the line given the graph

You will often find that you need to find the equation of a line given a point on the line and the gradient.

Rule to remember:

- y – y
_{1}= m (x – x_{1})

Comparing y=mx+c to this new method

As part of my series on coordinate geometry I show you how to find the distance between two points.

In this video I show you how to find the coordinates of the mid-point of a line segment.

In this next example, I show you how to find the equation of a parallel line to a given line passing through a given point.

**Examples in the video**

- Find the equation of a line parallel to the line 3y – 2x – 6 = 0 and passing through the point (-1, -2).

In this next example, I show you how to find the equation of a perpendicular bisector between two given points.

**Examples in the video**

- Find the equation of the perpendicular bisector of the line joining the points A(3,5) and B(-2,-1) giving your answer in the form ax + by + c = 0 where a, b and c are integers.

### Summary exercise

test