$解：? (1)?將點?A?代入一次函數(shù)表達式，?b=2×1-3?$
$∴?b=-1?$
$將點?A(1，??-1)?代入二次函數(shù)表達式，?-1=a×1?$
$解得?a=-1?$
$∴?a=-1，??b=-1?$
$?(2)?聯(lián)立兩個函數(shù)表達式得：?- x2= 2x- 3?$
$?x_{1}=1，??x_{2}=-3?$
$令?x=-3，??y=-9?$
$∴?B(-3，??-9)?$
$?(3)S_{△AOB}=4×9-\frac {1}{2}×1×1-\frac {1}{2}×3×9-\frac {1}{2}×4×8=6?$
