Linear Math: Find a and b for Point on Line

[~Sam~]

Homework Statement

Find a and b such that the point (a,b,0) lies on the line passing through (-1,-1,6) and (-9,7,2)

Homework Equations

Basic line equations, from P to Q= Q-P..etc

The Attempt at a Solution

I keep getting the wrong answer, but I got a point at exactly P (-1,-1,6) and a direciton by doing Q-P...and solving for z=0...

 

[lanedance]

so the line equation is
L(t) = P + t*(Q-P)

show your work, but soudns like you're heading in the right direction, solve for t, when z=0 as you say, then substitute back into line