?$解:設?y_1=m(x+3),??y_2=\frac {k}{x2}?$?
?$ 所以?y=y_1-y_2=m(x+3)-\frac {k}{x2}?$?
?$ 由題意可得:?\begin {cases}{m(1+3)-\frac {k}{(-1)2}=-2 } \\{m(-3+3)-\frac {k2}{(-3)2}=2} \end {cases}?$?
?$ 解得?m=-5,??k=-18?$?
?$ 所以?y=-5(x+3)+\frac {18}{x2}?$?
?$ 當?x=-1?時,?y=8?$?