Answer:
[tex]f\text{ = 5}[/tex]Explanation:
Here, we want to solve the given equation
To do this,we have to isolate f on the left hand side of the equation
To do the isolation, we have to bring 8 to the right
What this mean is that it is going to cross the equality sign and that changes its sign from positive to negative
Mathematically, we have this as:
[tex]\begin{gathered} f\text{ + 8 = 13} \\ f\text{ = 13-8} \\ f\text{ = 5} \end{gathered}[/tex]