设首项a1,公比是q 则a3a5+a2a10+2a4a6=a1^2q^6+a1^2q^10+2a1^2q^8=100 =[a1(q^3+q^5)]^2=100 所以a1(q^3+q^5)=10或-10 a4+a6=a1(q^3+q^5)=10或-10