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