EXAMPLE 4 The function x, x 1 Third formula is dened on the entire real line but has values given by different formulas, depending on the position of x. The values of f are given by y = -x when x 1. The function, however, is just one function whose domain is the entire set of real numbers (Figure 1.9). I Consider the function f(:I:) : |a:5| | |$+7|. (3] Write the function x) as a piece-wise dened function, where the pieces are linear functions. (That is, write x) using cases, as in Example 4 on page 6, but without using absolute values.) (b) Use part (a) to sketch the graph of the function (by hand)