2a+b=-5 3a-2b=-11
4a+2b=-10 ==> 7a=-21 ==> a=-3 b=1
AB=4
因为S=6 ==> 4*c/2=6 ==>c=3
A(-3,0) B(1,0) C(0,3)
2) SΔPAB=2 ==》 1/2 * AB * t =2 1/2 * 4 *t =2 => t=1
P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