ABSTRACT
The gradient or slope of a straight line is the ratio of the change in the value of y to the change in the value of x between any two points on the line. If, as x increases, (!), y also increases ("), then the gradient is positive. In Fig. 27.3(a),
the gradient of AC D change in y change in x
D CB BA
D 7 3 3 1 D
4 2
D 2 If as x increases (!), y decreases (#), then the
In Fig. 27.3(b), the gradient of DF D change in y
change in x D FE ED
D 11 23 0 D 9
3 D 3 Figure 27.3(c) shows a straight line graph y D 3. Since the straight line is horizontal the gradient is zero.
