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