A function is a relation in which each input value (x-value) has one and only one output value (y-value).
You have the following Linear function:
[tex]j\mleft(x\mright)=4x+11[/tex]According to the explained in the problem, you must find an input value that gives you 13 as the output value. Knowing this, you can say that:
[tex]j(x)=13[/tex]Substitute this value into the given function:
[tex]\begin{gathered} j(x)=4x+11 \\ 13=4x+11 \end{gathered}[/tex]The final step is to solve for "x".
Therefore, the value of "x" so that the function has the given value 13, is:
[tex]\begin{gathered} 13-11=4x \\ 2=4x \\ \frac{2}{4}=x \\ \\ x=\frac{1}{2} \end{gathered}[/tex]