?$解:設一次函數(shù)\ y=k x+b\ 的圖象與\ x\ 軸交點的坐標為\ (a, 0) ,$?
?$又其交點的縱坐標是 -2 ,$?
?$\therefore \frac{1}{2} \times|a| \times|-2|=1,\ $?
?$\therefore|a|=1,\ $?
?$\therefore a= \pm 1,$?
?$即圖象與\ x\ 軸交點的坐標為\ (1,0)\ 或\ (-1,0)\ 。$?
?$(1)當圖象與坐標軸的交點是\ (1,0)\ 和\ (0,-2) 時,$?
?$\left\{\begin{array} { l } { k + b = 0 } \\{ b = - 2 }\end{array} \text { , 解得: } \left\{\begin{array}{l}k=2 \\b=-2\end{array},\right.\right.\ $?
?$\therefore y=2 x-2 ;$?
?$(2) 當圖象與坐標軸的交點是\ (-1,0)\ 和\ (0,-2)\ 時,$?
?$\left\{\begin{array} { l } { - k + b = 0 } \\{ b = - 2 }\end{array} \text { ,解得: } \left\{\begin{array}{l}k=-2 \\b=-2\end{array},\right.\right.\ $?
?$\therefore y=-2 x-2 .$?
?$故答案為:\ y=2 x-2 , 或\ y=-2 x-2 .$?
?$ $?
?$ $?
