丨a-b-1丨与3（a-2b+3）^2互为相反数丨a-b-1丨+3（a-2b+3)^2=0丨a-b-1丨=0 3（a-2b+3)^2=0a-b=1a-2b=-3 a=5 b=4
因为丨a-b-1丨>=0,3（a-2b+3）^2>=0所以a-b-1=0,a-2b+3=0所以a=5,b=4
