(35-X)(26-X)=850 用配方法

910-61x+x^2=850
x^2-61x+60=0
(x-30.5)^2+60-930.25=0
(x-30.5)^2=870.25
x-30.5=29.5,x-30.5=-29.5
x=60,x=1

(35-X)(26-X)=850
乘开
910-35X-26X+X方=850
化简
X方-61X+60=0
(X-1)(X-60)=0
解得
X=1或60

850=910-61X+X^2
X^2-61X+60=0
(X-61/2)^2-930.25+60=0
(X-61/2)^2=870.25
X-61/2=59/2或-59/2
x=60或1

910-61x+x^=850
x^-61x+60=0
(x-30.5)^=870.25
x-30.5=±29.5
x1=1 x2=60

850=34*25,840=(-25)*(-34) 所以35-x=34或35-x=-25.
所以x=1或x=60