The expression for the function f is defined as,
f( x )={ kx+1, if x≤5 3x−5, if x>5 }
The left hand limit of the function at x=5 is,
lim x→ 5 − f( x )= lim x→ 5 − ( kx+1 ) = lim x→5−h ( kx+1 ) = lim h→0 ( k( 5−h )+1 ) =5k+1
The right hand limit of the function at x=5 is,
lim x→ 5 + f( x )= lim x→ 5 + ( 3x−5 ) = lim x→5+h ( 3x−5 ) = lim h→0 ( 3( 5+h )−5 ) = lim h→0 ( 15+3h−5 )
Solve for the right hand limit.
lim x→ 5 + f( x )=15−5 =10
The exact value of the function for x=5is,
f( x=5 )=kx+1 =5k+1
The condition for continuity of the function f at x=5 is fulfilled if left hand limit, right hand limit and the value at that specified point are equal.
It is observed that,
lim x→ 5 − f( x )= lim x→ 5 + f( x )=f( x=5 ) 5k+1=10=5k+1 5k=9 k= 9 5