Help please!! (1 Viewer)

[flowerp]

Hi every1,

I need help with the following question please:

If points (-3k,1), (k-1,k-3) and (k-4,k-5) are collinear, find the value of k.

Thanks !!

 

[boredofstudiesuser1]

Hi every1,

I need help with the following question please:

If points (-3k,1), (k-1,k-3) and (k-4,k-5) are collinear, find the value of k.

Thanks !!

If they're collinear, each segment is going to have the same gradient. (use gradient formula) m=(y2-y1)/(x2-x1)

A(-3k,1) B(k-1,k-3) C(k-4,k-5)

m of AB: (k-3-1)/(k-1-(-3k)) = (k-4)/(4k-1)

m of BC: (k-5-(k-3))/(k-4-(k-1)) = -2/-3 = 2/3

so we know 2/3 = (k-4)(4k-1)
8k-2 = 3k-12
5k = -10
k=-2

Hopefully that's the right answer.