3x^2+axy-2y^2+1与2bx^2-3xy+y^2的差值与x的取值无关(3x^2+ary-2y^2+1) - (2bx^2-3xy+y^2)=(3-2b)x^2+(a+3)xy+(-2-1)y^2+13-2b=0；a+3=0a=-3,b=3/22（a^2-2ab+b^2）-3(b^2-a^2) =2a^2-4ab+2b^2-3b^2+3a^2=5a^2-4ab-b...