Question

Para que os pontos A(-2,-4), B(-1,-2) e C(x,6), estejam alinhados. O valor de x será?

Answer 1

Resposta:

x = 3

Explicação passo a passo:

$\left|\begin{array}{cccc}-2&-1&x&-2\\-4&-2&6&-4\end{array}\right|_{+}^{-}=0\\\\|-2.(-2)-1.6+x(-4)-(-4)(-1)-(-2)x-6(-2)|=0\\\\|4-6-4x-4+2x+12|=0\\\\|-2x+6|=0\\\\-2x+6=0\\\\-2x=-6\\\\2x=6\\\\x=\frac{6}{2} \\\\x=3$