Analysis and Approaches for IBDP Maths Ebook 1 | Page 88

Your Practice Set – Analysis and Approaches for IBDP Mathematics
30
Paper 1 Section A – Finding the
equation of a straight line
Example
A straight line L passes through the points (3, 2) and (10,16) .
(a)
Find the equation of L , giving the answer in general form.
(b) Write down the x -intercept and the y -intercept of L .
[3]
[2]
Solution
(a)
The gradient of L
16 � 2
�
10 � 3
(M1) for valid approach
� 2
The equation of L :
y� 2 � 2( x� 3)
A1
y� 2 � 2x�
6
2x� y� 4 � 0
A1 N2
(b) The x -intercept of L is 2 A1
The y -intercept of L is � 4
A1 N2
[3]
[2]
Exercise 30
1. A straight line L passes through the points (10, 6) and (20,11) .
(a)
Find the equation of L , giving the answer in general form.
(b) Write down the x -intercept and the y -intercept of L .
[3]
[2]
2. A straight line L passes through the points ( �4, � 8) and (2, � 26) .
(a)
Find the equation of L , giving the answer in general form.
(b) Write down the x -intercept and the y -intercept of L .
[3]
[2]
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