Use the distributive property on the left side:

$\displaystyle-{6}{h}-{3}\le-{4}{h}+{7}\usepackage{cmbright}\Huge\$

Add 3 to both sides: $\displaystyle-{6}{h}\le-{4}{h}+{10}\usepackage{cmbright}\Huge\$

Add $\displaystyle{4}{h}\usepackage{cmbright}\Huge\$ to both sides: $\displaystyle-{2}{h}\le{10}\usepackage{cmbright}\Huge\$

Divide both sides by $\displaystyle-{2}\usepackage{cmbright}\Huge\$ : $\displaystyle{h}\ge-{5}\usepackage{cmbright}\Huge\$