急急急急急!!!解方程!!(要列明步驟)

(1000 - y)(80 - y12.5)=12.5
(80 - y12.5)*12.5=1000-y
80*12.5-y12.5*12.5=1000-y
1000-y=1000-y
所以y是任何實數!!!

2008-07-24 10:47:43 補充：
(1000 - 12.5 ÷ x) ÷ (180 - x) = 12.5

(1000 - 12.5 ÷ x)=12.5(180 - x)

(1000 - 12.5 ÷ x)=2250-12.5x

(1000 - 12.5 ÷ x)x=(2250-12.5x)x

1000x-12.5=2250x-12.5x^2

12.5x^2-1250x-12.5=0

x^2-100x-1=0

你係咪打錯題目??