Find the equation of line l in the figure below

Picture of the Figure:

http://i56.tinypic.com/ajum54.png

Please tell me how you got the equation. I spent so much time on this and still don't know how to figure it out..

NOTE: WRITE THE EQUATION STARTING WITH y=

First notice that P and Q are on the line, And on the parabola, y= x^2+1

For Q, the x coordinate is 4, so y = 16+1=17

Q(4,17)

For P, the y coordinate is 23, and the x is negative

23= x^2+1
x=-sqr(22)

P(-sqr22,23) and Q (4,17) are on line L.

Slope = -6/(4+sqr22)= -6/(4+sqr22) * (4- sqr22)/(4-sqr22)

= -6(4-sqr22)/(16-22)=-6*(4-sqr22)/(-6)= (4-sqr22)

Now you could get a decimal approximation for the slope and P and Q.
But I don't know what the instructions were.

So use point slope: y-17=(4-sqr22)(x-4)

Y=(4-sqr22)(x-4)+17

Hoping this helps!