Question

for what value of x the point A( 1,2) b( - 4,7 )and C( X, - 1) are collinear

Answer 1

please mark as the brainliest answer

Answer 2

Answer:

If the points are collinear then their are will be 0.

A(1,2)

B(-4,7)

C(x,-1)

$x1 = 1 \\ x2 = - 4 \\ x3 = x \\ y1 = 2 \\ y2 = 7 \\ y3 = - 1$

$\frac{1}{2} (x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)) = 0 \\ \\ (x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)) = 0 \\ \\ 1(7 + 1) - 4( - 1 - 2) + x(2 - 7) = 0 \\ \\ 1(8) - 4( - 3) + x( - 5) = 0 \\ \\ 8 + 12 - 5x = 0 \\ \\ 20 = 5x \\ \\ x = 4$

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