Question

Ache o valor de X para que os pontos A(x,3),B(-2,-5) e C(-1,-3)sejam colineares

Answer 1

$\left[\begin{array}{ccc}x&3&1\\-2&-5&1\\-1&-3&1\end{array}\right] = 0 \\ \\ \\ \\ (-5x - 3 - 6) - (5 - 3x - 6) = 0 \\ -5x - 3 -6 - 5 + 3x + 6 = 0 \\ -2x-8 = 0 \\ 2x = -8 \\ \\ x = \frac{-8}{2} \\ \\ x = -4$