Question

1) Determinar a equação geral da reta que passa pelos pontos A(1.2) e B(5,5)

2) Determinar a equação geral da reta que passa pelos pontos A(0, 2) e B(-1.4).​

Answer 1

1)

$\mathsf{\begin{vmatrix}1&2&1\\5&5&1\\x&y&1\end{vmatrix}=0}$

$\mathsf{1(5-y) -2(5-x) +1(5y-5x)=0}\\\mathsf{5-y-10+2x+5y-5x=0}$

$\boxed{\boxed{\mathsf{-3x+4y-5=0}}}$

2)

$\mathsf{\begin{vmatrix}0&2&1\\-1&4&1\\x&y&1\end{vmatrix}=0}$

$\mathsf{-2(-1-x) +1(-y-4x)=0}\\\mathsf{2+2x-y-4x=0}$

$\mathsf{-2x-y+2=0\times(-1)}$

$\boxed{\boxed{\mathsf{2x+y-2=0}}}$