(40+Y)(1+X)=154
Y(1-X)=90
Y=90/(1-X)
代入(40+Y)(1+X)=154
[40+90/(1-X)]*(1+X)=154
(40-40X+90)/(1-X)*(1+X)=154
(130-40X)(1+X)=154(1-X)
-40X^2+90X+130=154-154X
10X^2-61X+6=0
(10X-1)(X-6)=0
X=1/10,X=6
X=1/10,Y=90/(1-X)=100
X=6,Y=90/(1-X)=-18