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    Question:
    2 intersecting lines have the equation r_1 = (2,9,13) +s(1,2,3) and r_2 = (λ, 7,-2) + t(-1,2,-3). Find λ.

    What I did was equate the x and z values of the lines and do simultaneous equations to eliminate the other variables. So i.e:

    x: s+t = λ -2 (1) (then multiplied by 3)
    z: 3s + 3t = -15 (2)

    The answer I got was λ = -3. But the back of the book says -6. Can someone spot where I'm going wrong please? Is this even the right approach to take?

    Thank you.
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    (Original post by HotCoco.)
    Question:
    2 intersecting lines have the equation r_1 = (2,9,13) +s(1,2,3) and r_2 = (λ, 7,-2) + t(-1,2,-3). Find λ.

    What I did was equate the x and z values of the lines and do simultaneous equations to eliminate the other variables. So i.e:

    x: s+t = λ -2 (1) (then multiplied by 3)
    z: 3s + 3t = -15 (2)

    The answer I got was λ = -3. But the back of the book says -6. Can someone spot where I'm going wrong please? Is this even the right approach to take?

    Thank you.
    I also get lambda as - 3
 
 
 
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