Question

if point (4, 5) is on the graph of a function, which equation must be true?
○ $f(5)=4$
○ $f(5,4)=9$
○ $f(4)=5$
○ $f(5,4)=1$

Explanation:

Step1: Recall function notation

For a function \( y = f(x) \), a point \((a, b)\) on the graph means \( f(a)=b \).

Step2: Apply to given point

The point is \((4, 5)\), so \( x = 4 \) and \( y = 5 \). Thus, \( f(4)=5 \).

Answer:

\( f(4)=5 \) (the third option)