Correct. Since the given line has slope $\displaystyle\frac{{3}}{{5}}\usepackage{cmbright}\Huge\$ , a line perpendicular to it will have slope $\displaystyle-\frac{{5}}{{3}}\usepackage{cmbright}\Huge\$ (the opposite reciprocal of $\displaystyle\frac{{3}}{{5}}\usepackage{cmbright}\Huge\$ ).