What are the 2 things you are not sure about evaluating functions

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. 1. Given the function f (x) = 3x - 5, find f (4).

A function is a relation in which each input has only one output. In the relation , y is a function of x, because for each input x (1, 2, 3, or 0), there is only one output y. x is not a function of y, because the input y = 3 has multiple outputs: x = 1 and x = 2.

A formula is an expression which calculates the value of a cell. Functions are predefined formulas and are already available in Excel. For example, cell A3 below contains a formula which adds the value of cell A2 to the value of cell A1.

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