What is the equation of a straight line? Describe what all the terms within the equation do.

The equation of a straight line is: y = mx + c
There is a 'y term', y, and an 'x term', x.
The gradient of the line, m, is the slope of the straight line. The larger the value of m, the steeper the slope.
The 'y-intercept', c, is the point that the straight line crosses the y axis (at x=0), when the line is drawn on an x-y graph. If c=0, the straight line passes through the 'origin'.