高校问答别对我撒谎翼苏轼的鬼:初一数学二元一次方程求解题1道(2)
来源：百度文库 编辑：高校问答 时间：2024/05/09 00:20:24
如果2X+(A-1)Y=2B/A,2X+(B-1)Y=2A/B,且A不等于B,求代数式2X+(A+B-1)Y+3的值
2X+(A-1)Y=2B/A
2X+(B-1)Y=2A/B
两式相减：
(A-1)Y-(B-1)Y=2B/A-2A/B
(A-B)Y=2(B^2-A^2)/AB
Y=-2(A+B)/AB
2X+(A+B-1)Y+3
=2X+(A-1)Y+BY+3
=2B/A+BY+3
=2B/A-2(A+B)/A+3
=-2+3
=1