先化簡再求值1。當a=-2時求(a/a+1+1)/(11-3a^2/1-a^2)的值

熱心網友

(a/a+1+1)/(11-3a^2/1-a^2)=(a/a+1+1)(1-a^2)/(11-3a^2)=[a(1+a)(1-a)/a+1-a^2]/(11-3a^2)=(a-a^2+1-a^2)/(11-3a^2)=(a+1)/(11-3a^2)當a=-2時 (a+1)/(11-3a^2)=(-2+1)/(11-3*(-2)^2)=-1/(11-12)=-1/-1=1