Gerald purchased 55 paving stones to use in his garden. the graph shows points representing the number of stones left to place at several different times while gerald is working. a function graph of a line segment having three points (0,55), (3,40) and (7, 20) with an x axis of zero to twelve hours and a y axis of zero to sixty paving stones left select from the drop-down menus to complete the equation, in standard form, that represents the relationship between the number of paving stones left to place, y, and the time, x, gerald has spent working. x + y =