Answer:
The function whose graph is given to us is:
[tex]f(x)=\log (x-3)[/tex]
Step-by-step explanation:
By looking at the graph of the function f(x) we observe that when x=4 then the value of the function is zero.
i.e. f(x)=0 at x=4.
( If:
[tex]f(x)=\log (x+3)[/tex]
then at x=4 we have:
[tex]f(x)=\log 7\neq 0[/tex]
If:
[tex]f(x)=\log x+3[/tex]
then at x=4 we have:
[tex]f(x)=\log 4+3\neq 0[/tex]
( since, [tex]\log 4>0[/tex]
If:
[tex]f(x)=\log x-3[/tex]
then at x=4 we have:
[tex]f(x)=\log 4-3\neq 0[/tex]
since,
[tex]0<\log 4<1\\\\Hence,\\\\-3<\log 4-3<1-3\\\\i.e.\\\\-3<\log 4-3<-2\\\\i.e.\\\\-3<f(4)<-2[/tex] )
Hence, the only function which satisfies this property is:
[tex]f(x)=\log (x-3)[/tex]
since, at x=4
we have:
[tex]f(x)=\log (4-3)\\\\i.e.\\\\f(x)=\log 1\\\\i.e.\\\\f(x)=0[/tex]
Hence, the answer is:
[tex]f(x)=\log (x-3)[/tex]