For what values of k are the points (8,1), (3,-2k) and (k,-5) collinear?
SUPER URGENT PLS!!!
MisterMeow:
I am not a maths student but ... I guess that's about making an equation :3
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arΔABC = 0 where A(8,1), B(3,-2k) and C(k,-5)
arΔABC= 0 = [8 (-2k+5) + 3(-5-1) + k(1+ 2k)] (ar is zero because collinear pts)
0 = -16k + 40 - 18 + k + 2k²
2k² - 15k + 22 = 0
2k² - 4k - 11k + 22 = 0
2k(k-2) -11(k-2) = 0
(2k-11) (k-2) = 0
∴k= 11/2 or 2
arΔABC= 0 = [8 (-2k+5) + 3(-5-1) + k(1+ 2k)] (ar is zero because collinear pts)
0 = -16k + 40 - 18 + k + 2k²
2k² - 15k + 22 = 0
2k² - 4k - 11k + 22 = 0
2k(k-2) -11(k-2) = 0
(2k-11) (k-2) = 0
∴k= 11/2 or 2
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