Question

Where does the line that passes through the points P=(3,-1,2) and Q=(5,8,4) pierce the X-Y plane?

Answer 1

define the vector between them first

Answer 2

once you have the vector, you can create the equation to define every point on the line

x = xo + at
y = yo + bt
z = zo + ct

and since the xy plane is the z=0 plane; use the z equation to define t for z=0; then use that to determine x and y

Answer 3

or, we can continue the shuffiling generally

0 = zo + ct ; when t=-zo/c ; therefore the point will be

(xo + a(-zo/c), yo + b(-zo/c), zo + c(-zo/c))

Answer 4

Ok I think am getting some idea ,
but I actually jxt saw the question and cudnt ans it!

Answer 5

aslong as we know how to define a vector between 2 points, the general setup of the point just needs filled in by the <a,b,c> vector parts:)

Answer 6

and of course the xo,yo,zo are one of the points that had been given

Answer 7

Oh Ok!
I will try to solve it then!
Anyway thanks for your help!!!!!!!!!!!