# Linear algebra, parametric equation, intersectin of line

#### cleopatra

1. Homework Statement

Two equations for two planes in 3-D
2x+y-2z=1
x-2y+z=-3
Find the parametric equation for the line of intersection of the two planes by solving these two equations togeather.

3. The Attempt at a Solution

Gauss Jordan gives:
1 0 -3/5 -1/5
0 1 -4/5 7/5

if z=t
x=3/5t-1/5
y=4/5t+7/5

I don´t know how to finish the problem.

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#### yyat

You have already solved the problem!

x=3/5t-1/5
y=4/5t+7/5
z=t

is the parametric equation for the intersection.

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#### Dick

Homework Helper
You are already finished. z=t, x=(3/5)t-1/5 and y=(4/5)t+7/5 is the intersection line in parametric form. Are you supposed to express it in vector form or something?

#### cleopatra

really? I thought this was only the parametric equation and I had to find some special line of intersection as well.

#### Dick

Homework Helper
really? I thought this was only the parametric equation and I had to find some special line of intersection as well.
Nah. The problem says find the line that is the intersection of the two planes. No line intersection involved.

#### cleopatra

okey thanks for that

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