When $\displaystyle{x}={3}\usepackage{cmbright}\Huge\$ and $\displaystyle{y}=-{4}\usepackage{cmbright}\Huge\$ then $\displaystyle{y}+{3}=-{1}\usepackage{cmbright}\Huge\$ and $\displaystyle{2}{\left({x}-{4}\right)}=-{2},\usepackage{cmbright}\Huge\$ so $\displaystyle{y}+{3}\ne{2}{\left({x}-{4}\right)}\usepackage{cmbright}\Huge\$ when $\displaystyle{\left({x},{y}\right)}={\left({3},-{4}\right)}\usepackage{cmbright}\Huge\$ . Therefore (3, -4) does not lie on the line.