Question

Obter a função do primeiro grau que passa pelos pontos P = (1, 3) e Q = (2, 8)

Answer 1

$\begin{vmatrix}x&y&1\\1&3&1\\2&8&1\end{vmatrix}=0\\\\\begin{bmatrix}x&y&1&|&x&y\\1&3&1&|&1&3\\2&8&1&|&2&8\end{bmatrix}=0\\\\3x+2y+8-6-8x-y=0\\y-5x+2=0\\\boxed{y=5x-2}$