Question

Encotre a equação da reta dos pontos abaixo:

A)  a(1,4) e c(1,2)

B)  a(1,2) e m(3,4)

Answer 1

$<var>A)\left[\begin{array}{ccc}x&y&1\\1&4&1\\1&2&1\end{array}\right]=0\\\\\ [(x.4.1)+(1.2.1)+(y.1.1)]-[(4.1.1)+(y.1.1)+(2.1.x)]=0\\\ [4x+2+y] -[4+y+2x]=0\\4x+2+y-4-y-2x=0\\2x-2=0\\x=\frac{2}{2}=>x=1\\\\</var>$

 

 

$<var>B)\left[\begin{array}{ccc}x&y&1\\1&2&1\\3&4&1\end{array}\right]=0\\\\\ [(x.2.1)+(1.4.1)+(y.1.3)]-[(3.2.1)+(y.1.1)+(4.1.x)]=0\\\ [2x+4+3y] -[6+y+4x]=0\\2x+4+3y-6-y-4x=0\\-2x+2y-2=0\ (/2)\\-x+y-1=0\\y=x+1</var>$