Answer:
15
Step-by-step explanation:
Just substitute the x for 5
In this case:
Original function: f(x) = [tex]x^{2}[/tex] - 2x
Substitute function: f(5) = [tex](5)^{2}[/tex] - 2(5)
Now solve for the substitute function
[tex](5)^{2}[/tex] - 2(5)
25 - 10
15
Therefore, f(5) is equal to 15
