The graph begins at $\displaystyle{\left(-{2},{1}\right)}\usepackage{cmbright}\Huge\$ , so 2 should be added inside the square root, and 1 should be added outside the square root. The graph decreases, so there should be a negative sign in front of the radical. The graph is wider than the basic $\displaystyle{f{{\left({x}\right)}}}=\sqrt{{x}}\usepackage{cmbright}\Huge\$ , so the square root should be multiplied by a number greater than 1. The function $\displaystyle{f{{\left({x}\right)}}}={1}-{3}\sqrt{{{x}+{2}}}\usepackage{cmbright}\Huge\$ matches these conditions.