题目应是(x-y-3)²和|4x-3y+11|互为相反数
(x-y-3)²+|4x-3y+11|=0
x-y-3=0 (1)
x=y+3
4x-3y+11=0 (2)
4(y+3)-3y+11=0
4y+12-3y+11=0
y=-23
x=-20