Apps. and Interpretation for IBDP Maths Ebook 1 | Page 110

Your Practice Set – Applications and Interpretation for IBDP Mathematics
(b) The equation of L
1
:
1
y�3 � ( x� 0)
2
(M1) for substitution
2y�6� x
(A1) for simplification
x� 2y� 6 � 0
A1 N3
(c) The equation of L
2
is
(d)
The coordinates of C
1
y � x. A2 N2
2
�0 �6 3�6
�
� � , �
(A1) for substitution
� 2 2 �
� (3, 4.5)
A1 N2
(e) The gradient of L
3
1
� �1�
2
�� 2
(A1) for correct value
The equation of L
3
:
y� 4.5 � �2( x� 3)
(M1) for substitution
y� 4.5 � �2x�
6
2x� y�10.5 � 0
4x� 2y� 21 � 0
A1 N3
(f) 4x � 2(0) � 21 � 0
(M1) for substitution
(g)
x � 5.25
Thus, the x -intercept of L
3
is 5.25. A1 N2
�1
�
4x� 2�
x�� 21 � 0
(M1) for substitution
�2
�
5x �21 � 0
x � 4.2
1
y � (4.2)
(M1) for substitution
2
y � 2.1
Thus, the coordinates of D are (4.2, 2.1). A1 N3
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