Help with lines of intersection

Find the equation of the line of intersection of the two planes:
x-y=3 and x +2y+3z=0

I'm not sure if I'm doing this right.
x=3+y
3+3y+3z=0
y=-z-1

or do I take the cross product of <1,-1,0>X<1,2,3> with the point (0,0,-3)?

Thanks in advance.

Quote:

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Originally Posted by khuezy

Find the equation of the line of intersection of the two planes:
x-y=3 and x +2y+3z=0

I'm not sure if I'm doing this right.
x=3+y
3+3y+3z=0
y=-z-1

or do I take the cross product of <1,-1,0>X<1,2,3> with the point (0,0,-3)?

Thanks in advance.

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You do it like the one you were shown here: http://www.mathhelpforum.com/math-he...-equation.html

That will give you the line of intersection in parametric form.