This is linear equation with connecting two points.

\(\displaystyle{\left({x}_{{1}},{y}_{{1}}\right)}-{\left(-{7},{3}\right)}\)

\(\displaystyle{\left({x}_{{2}},{y}_{{2}}\right)}={\left({6},{3}\right)}\)

Linear eqution

\(\displaystyle{\left({y}-{y}_{{1}}\right)}=\frac{{{y}_{{2}}-{y}_{{1}}}}{{{x}_{{2}}-{x}_{{1}}}}{\left({x}-{x}_{{1}}\right)}\)

y-3=0 or y=3

This is the graph of y=3.

\(\displaystyle{\left({x}_{{1}},{y}_{{1}}\right)}-{\left(-{7},{3}\right)}\)

\(\displaystyle{\left({x}_{{2}},{y}_{{2}}\right)}={\left({6},{3}\right)}\)

Linear eqution

\(\displaystyle{\left({y}-{y}_{{1}}\right)}=\frac{{{y}_{{2}}-{y}_{{1}}}}{{{x}_{{2}}-{x}_{{1}}}}{\left({x}-{x}_{{1}}\right)}\)

y-3=0 or y=3

This is the graph of y=3.