Maths Straight Line Graphs

The table of three values method

1) choose three values of x and draw up a table 2) work out the y values 3) plot the coordinates and draw a line

How to find the gradient

Find two accurate points and complete the triangle (keep the numbers positive) Find the change in y and the change in x Use: change in y/change in x

Sketching a straight line using y=mx+c

Get the equation into form Put a dot on the y axis at the value of c Go along one unit up or down by the value of m and make another dot Repeat the same step in both directions Finally, check

What is "a"

Gradient, shows the steepness of a line

Finding the Austin of a straight line graph

Identify two variables on the axis Find the gradient and intercept Using these values write down equation

Real life gradients

Vertical change/Horizontal change

Vertical line

X

Horizontal line

Y

Downhill diagonal from left to right

y=-x

Sloping lines

y=ax, y=-ax

Parallel lines

y=mx+c

Uphill diagonal from left to right

y=x