Incorrect.

$\displaystyle{y}={\log}_{{{5}}}{625}\usepackage{cmbright}\Huge\$ is equivalent to $\displaystyle{{5}}^{{y}}={625}\usepackage{cmbright}\Huge\$ . Try computing different powers of 5: $\displaystyle{{5}}^{{2}},{{5}}^{{3}},{{5}}^{{4}}\usepackage{cmbright}\Huge\$ . The correct answer is 4.