The provided function is f( x )= 4x 3x+4 under the domain f:R−{ − 4 3 }→R .
Consider y as an arbitrary element of range of the function f .
y= 4x 3x+4 x( 4−3y )=4y x= 4y 4−3y g( y )= 4y 4−3y
The inverse of the function be g( y )= 4y 4−3y in the range f→R−{ −4 3 }
gof( x )=g( f( x ) ) =g( 4x 3x+4 ) = 4( 4x 3x+4 ) 4−3( 4x 3x+4 ) = 16x 12x+16−12x = 16x 16 =x
fog( x )=f( g( x ) ) =f( 4y 4−3y ) = 4( 4x 3x+4 ) 4−3( 4x 3x+4 ) = 16y 12y+16−12y = 16y 16 =y
The inverse of the provided function is,
f −1 ( y )=g( y ) = 4y 4−3y
Thus, the option (B) is the correct option.