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Why is my C1 Line Intersection answer wrong? How would I do it? watch

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    I have attached the question to this post, along with my answer.

    My method for the intersection was:
    Put L1 in the form ax+by+c=0 to substitute in L2
    Solve this to get an equation in the form ax+by+c=0
    Put that equation in the form y=mx+c

    I got the answer (-7,7) and the correct answer was (17/3, 4/3). I don't get where I went wrong. How would I solve this correctly?

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    Thanks, appreciate it
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    (Original post by blobbybill)
    I have attached the question to this post, along with my answer.

    My method for the intersection was:
    Put L1 in the form ax+by+c=0 to substitute in L2
    Solve this to get an equation in the form ax+by+c=0
    Put that equation in the form y=mx+c

    I got the answer (-7,7) and the correct answer was (17/3, 4/3). I don't get where I went wrong. How would I solve this correctly?

    Name:  IMG_20170112_170419.jpg
Views: 23
Size:  494.6 KB

    Thanks, appreciate it
    first of all rearrange both l1 and l2 to give y as the subject of formula. SO L1 - y=x/2-3/2 and L2 - y= -2/5x + 18/5. Then make them equal each other so the full equation will be -2/5x +18/5 = x/2 - 3/2. Cancelling down to give x gives you 51/9 which is 17/3 =x Put x back into L1 (or any) and you should cancel down to get y on its own, giving y=4/3
 
 
 
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