Apps. and Interpretation for IBDP Maths Ebook 1 | Page 33

7
Paper 1 – Factorized Form
Example
Let
2
f ( x) � x � 2x
� 8 .
(a) Factorize f( x ).
(b) Write down the x -intercepts of the graph of f .
f( x ) reaches its minimum value at y �� 9.
[2]
[2]
4
(c) Write down the range of f .
[1]
Solution
(a) f ( x) � ( x � 2)( x � 4)
A2 N2
(b) x � 2 and x �� 4
A2 N2
(c) { y: y�� 9}
A1 N1
[2]
[2]
[1]
Exercise 7
1. Let
f x � x � x � .
2
( ) 2 35
(a) Factorize f( x ).
(b) Write down the x -intercepts of the graph of f .
f( x ) reaches its extreme value at y �� 36 .
[2]
[2]
(c) Write down the range of f .
[1]
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