8916102088894xyx^2-xy-2y^2=12x^2+y^21x^2-xy-2y^2=1（x+y）（x-2y）=1x+y=mx-2y=n（mn=1）x=2m+n3y=mn）32x^2+y^2=19（9m^2+3n^2+6mn=19（9m^2+3m^2+62+233m=n=22+233{an}a13a412{bn}b14b420{bnan}（{an}{bn}{bn}n9109a1500sp++