Formula for a straight line

The formula for a straight line is:

`y=mx+c`

The formula for this line is y = mx + c

Where `m=` Gradient

`c=` The point where the line crosses the `y` axis (`y` intercept)

Further explanation

Equations of a straight line are in the form of:

`y=mx+c`

If you are given a formula of a straight line and asked to draw it on a graph you do so as follows:

Examples

1. Draw the following straight line on a graph

`y=2x+3`

First lets calculate some points on the graph.

If `x=-2` then `y=2times(-2)+3=-1`

`x=-1` then `y=2times(-1)+3=1`

`x=0` then `y=2times0+3\ \ \ \ \ \ \ \ =3`

`x=1` then `y=2times1+3\ \ \ \ \ \ \ \ =5`

`x=2` then `y=2times2+3\ \ \ \ \ \ \ \ =7`

Now draw a graph and plot the above points.

Plot your new positions on a graph

Now draw a straight line through these points

Connect the dots now this straight line is y = 2x + 3

2. Draw the following straight line on a graph

`y=-2x+5`

First lets calculate some points on the graph.

If `x=-2` then `y=-2times(-2)+5=9`

`x=-1` then `y=-2times(-1)+5=7`

`x=0` then `y=-2times0+5\ \ \ \ \ \ \ \ =5`

`x=1` then `y=-2times1+5\ \ \ \ \ \ \ \ =3`

`x=2` then `y=-2times2+5\ \ \ \ \ \ \ \ =1`

Now draw a graph and mark out the above points.

Draw the new set of positions on a graph

Now draw a straight line through these points

This line has a formula of y = -2x + 5