Reading Graphs
Linear Graphs and y = mx + c
A graph that has a straight line is called a linear graph:

The vertical axis is the yaxis, while the horizontal axis is called the xaxis

The gradient, or slope, of the line is given the symbol 'm'

The line crosses the yaxis when x = 0 at the yintercept, given the symbol 'c'
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Calculating the gradient, or slope, of a linear graph is an important skill to master:

Draw a large triangle onto the line

Work out the coordinates of the two points where the triangle meets the line

Divide the change in y value by the change in x value
Calculating Gradients: Example A
A worked example where the gradient of a straight line is calculated.
Calculating Gradients: Example B
Another example of how to calculate the gradient of a line.
Drawing Tangents to a Curve [often higher tier only]
Sometimes you need to work out the slope at a particular point on a curve:

Carefully draw a straight line with a ruler that just touches the curve

Work out the gradient of this straight line in the usual way
Tangents: Example
A worked example where a tangent is used to find the gradient of a curve at a point.
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