1)2a+b=-5 3a-2b=-114a+2b=-10 ==> 7a=-21 ==> a=-3 b=1AB=4 因为S=6 ==> 4*c/2=6 ==>c=3A(-3,0) B(1,0) C(0,3)2) SΔPAB=2 ==》 1/2 * AB * t =2 1/2 * 4 *t =2 => t=1P点坐标x任意 y=1 ==》(x,1)3)角m=22.5 AIC=135 n=22.5结果=22.5+22.5/135