Xx28+Xx78=108000000000
Xx(28+72)=108000000000
Xx100=108000000000
X=10800000000000/100
X=10800000000
125000X+875000X=1234567890
X(125000+875000)=1234567890
1000000X=1234567890
X=1234567890/1000000
X=1234.56789
yyds yyds yyds yyds beybey
(X-9) ÷ (89-X) = 4
被除数 除数 商
则 根据被除数=商×除数 得出:
X-9=4(89-X)
X-9=356-4X
5X=365
X=73