How to Evaluate functions

Replace (substitute) its variable with a given number or expression. Like in this example: Example: evaluate the function f (x) = 2x+4 for x=5

Step-by-step explanation:

Plug in 5 for X

So you have 2 (5) + 4

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To evaluate a function, substitute the input (the given number or expression) for the function's variable (place holder, x). Replace the x with the number or expression. Given the function f (x) = 3x - 5, find f (4). Solution: Substitute 4 into the function in place of x.