设(1+x)=y
(2000y-1000)y=1320 →2000y^2-1000y-1320=0,y=11/10或-3/5 →x=1/10或-8/5
50(1+y+y^2)=182 →50y^2+50y-132=0,y=-11/5或6/5→x=-16/5或1/5
设(1+x)=y
(2000y-1000)y=1320 →2000y^2-1000y-1320=0,y=11/10或-3/5 →x=1/10或-8/5
50(1+y+y^2)=182 →50y^2+50y-132=0,y=-11/5或6/5→x=-16/5或1/5