已知x=(1-2t),
t=(1-x)/2
y=(5-2t)/(7-4t),
y=(5-2*(1-x)/2)/(7-4*(1-x)/2),
y=(5-1+x)/(7-2+2x),
y(5+2x)=4+x
5y+2xy=4+x
(2y-1)x=4-5y
x=(4-5y)/(2y-1)
已知x=(1-2t),
t=(1-x)/2
y=(5-2t)/(7-4t),
y=(5-2*(1-x)/2)/(7-4*(1-x)/2),
y=(5-1+x)/(7-2+2x),
y(5+2x)=4+x
5y+2xy=4+x
(2y-1)x=4-5y
x=(4-5y)/(2y-1)