Question

150/x+120/y=30 x-y=2

Answer 1

x=y+2

代入

150/(y+2)+120/y=30

5/(y+2)+4/y=1

两边乘y(y+2)

5y+4y+8=y^2+2y

y^2-7y-8=0

(y-8)(y+1)=0

y=8,y=-1

x=y+2

所以

x=10,y=8

x=1,y=-1