Y²＝2pxY＝2py0(x-p/2)/y0²-p²怎样联立这两条方程得到Y＝-p²/y0呢

Y²＝2pxY＝2py0(x-p/2)/y0²-p²怎样联立这两条方程得到Y＝-p²/y0呢
Y²＝2px
Y＝2py0(x-p/2)/y0²-p²怎样联立这两条方程得到Y＝-p²/y0呢

Y²＝2pxY＝2py0(x-p/2)/y0²-p²怎样联立这两条方程得到Y＝-p²/y0呢
y=2py0(x-p/2)/(y0^2-p^2)
=y0*(2px-p^2)/(y0^2-p^2)
=y0*(y^2-p^2)/(y0^2-p^2),
——》y*(y0^2-p^2)=y0*(y^2-p^2),
——》y0*y^2-(y0^2-p^2)y-y0*p^2=(y0*y+p^2)(y-y0)=0,
——》y-y0=0,即y=y0,
或y0*y+p^2=0,即y=-p^2/y0.