15 . Let f ( x)
5x
� . e
( a ) Find f 1 ( x)
.
�
( b ) Write down the range of
Let g( x) ( 3 ln x)
2
� � .
1 f � .
[ 3 ]
[ 1 ]
( c ) Express ( g f )( x ) in the form integers .
2 ax �bx � c , where a , b and c are
[ 3 ]
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