1, symmetry axis =-b/2a = 1, y= 1 when x = 1, and a=- 1, b=2, c=0 can be obtained by passing through the origin.

2. Since PM is an isosceles triangle, FM=FP, and PM is perpendicular to y=5/4, so the midpoint G connecting F and PM, FG is the median line of PM, then1/2pm = the distance from F to Y = 1/2, so PM= 1, so the ordinate of P is/.

3. Suppose there are n points, PN=x- 1 or 1-x PM=5/4-y, and from PM=PN there are x-1= 5/4-y y =-x 2+2x.

The solution is x=3/2 y=3/4=t, so there is t=3/4 to make PM=PN.