Page 129 - Mathematics

Solution y − y
(a) The slope of the line joining B(1, 2) and C(0, 1)− is given by m = 2 1 .
x − x 1
2
Let ( , ) (0, 1)xy = − and ( ,xy 2 ) (1, 2).=
2
1
1
2 ( 1)− −
Thus, m = Tanzania Institute of Education
10−
3
=
1

= 3
Therefore, the gradient of line BC is 3.

(b) The slope of the line joining B (1, 2) and D (–1, – 4) is given by
y − y
m = 2 1 . Let (x , y ) = (1, 2) and (x , y ) = (–1, – 4)
x − x 1 1 1 2 2
2
42
−−
Thus, m =
1 1
−−
− 6
=
− 2

= 3

Therefore, the slope of BDis 3.

In this example, it can be observed that the gradient of a straight line does not

change when different pair of points are used provided that all the points lie on
the same line.

Mathematics Form One

123

25/10/2024 09:51:46
Mathematics form 1.indd 123
Mathematics form 1.indd 123 25/10/2024 09:51:46