



 
Hi Alexis, The expression $y = x  1$ describes $y$ as a function if $x,$ just as $y = 3x + 4$ and $y = x^2  7$ describe $y$ as a function of $x.$ In the case of $y = x  1,$ given a value of $x,$ to calculate the associated value of $y,$ find the absolute value of $x$ and then subtract 1. Thus since $5 = 5,$ if $x= 5$ then $y = 5  1 = 5  1 = 4$ and since $3 = 3$ if $x = 3$ then $y = x  1 = 3  1 = 3  1 = 2.$ When I am introduced a function which is new to me I like to see its graph. I suggest you make a table of some values of $x,$ calculate the associated values of $y,$ plot the points on some graph paper and sketch the graph.
Select a few more values of $x,$ extend the table, plot the $(x, y)$ coordinates on some graph paper and sketch the graph. I hope this helps,




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