Answer :
he equation of the line through two points is:
[tex]\frac{y-y_1}{x-x_1}=\frac{y_2-y_1}{x_2-x_1}[/tex]replacing the values of x and y where: x1=1, x2=7, y1=1 and y2=-5
we have
[tex]\begin{gathered} \frac{y-1}{x-1}=\frac{-5-1}{7-1} \\ \frac{y-1}{x-1}=\frac{-6}{6} \\ \frac{y-1}{x-1}=-1 \\ y-1=1-x \\ y+x-2=0 \end{gathered}[/tex]