Correct. In this case, the Profit formula is $\displaystyle{P}={s}{q}-{10}{q}\usepackage{cmbright}\Huge\$ . Substituting $\displaystyle{q}=-{20}{s}+{1200}\usepackage{cmbright}\Huge\$ into the equation, you find $\displaystyle{P}={s}{\left(-{20}{s}+{1200}\right)}-{10}{\left(-{20}{s}+{1200}\right)}\usepackage{cmbright}\Huge\$ , which simplifies to $\displaystyle{P}=-{20}{{s}}^{{2}}+{1400}{s}-{12},{000}\usepackage{cmbright}\Huge\$ .