Friday

October 9, 2015
Posted by **J** on Monday, May 7, 2012 at 8:28pm.

- Calculus -
**Reiny**, Monday, May 7, 2012 at 9:06pmWe need the direction of their line of intersection....

double the 2nd plane equation, then add that to the 1st

x+2y-3z = -6

6x - 2y + 4z = 8

7x + z = 2

z = 2-7x

let x=1

then z = -5

back in the 1st

1 + 2y + 15 = -6

y = -11 -----------> point (1,-11,-5)

let x = 0

then z = 2

back in 1st

0+2y -6 = -6

y = 0 ------------> point (0,0,2)

direction vector of line of intersection of the planes = (1, -11, -7)

**so one such vector equation is**

r = (2,-1,7) + t(1,-11,-7)

(the question should have said, "Find a vector equation...."

since the answer I obtained is not unique)

- Calculus -
**J**, Monday, May 7, 2012 at 11:31pmWe need the direction of their line of intersection? That's all the question mentioned... so is that still the correct answer? :/