Defined by parabola: the distance from the point on the parabola to the focus is equal to the directrix.

y？ =4x，

Focus (1, 0),

X=- 1

∴ The distance from P to directrix F is the distance from P to F.

D = distance from p to f+distance from p to l >; = the distance from f to l,

At this time, p is on the vertical line from f to l.

l:4x-3y+6=0，

The slope is 4/3,

The slope of PF is -3/4.

F( 1，0)，

Then PF:

y=-(3/4)(x- 1)

Substitute y=-3(x- 1)/4 into the parabola.

9(x- 1)？ / 16=4x

arrange

9x？ -82x+9=(9x- 1)(x-9)=0，

X=9 or x= 1/9.

P is on the vertical line segment,

Then x < 1, that is, x= 1/9,

y=-(3/4)(x- 1)=2/3，

∴P( 1/9,2/3)