Note that $\displaystyle-{5}\usepackage{cmbright}\Huge\$ and 10 are excluded values. Multiply both sides by the common denominator $\displaystyle{\left({x}+{5}\right)}{\left({x}-{10}\right)}\usepackage{cmbright}\Huge\$ :

$\displaystyle\frac{{{6}{\left({x}+{5}\right)}{\left({x}-{10}\right)}}}{{{x}+{5}}}=\frac{{{3}{\left({x}+{5}\right)}{\left({x}-{10}\right)}}}{{{x}-{10}}}\usepackage{cmbright}\Huge\$

Simplify: $\displaystyle{6}{\left({x}-{10}\right)}={3}{\left({x}+{5}\right)}\usepackage{cmbright}\Huge\$

Distribute: $\displaystyle{6}{x}-{60}={3}{x}+{15}\usepackage{cmbright}\Huge\$

Solve for x: $\displaystyle{6}{x}={3}{x}+{75}\usepackage{cmbright}\Huge\$ , $\displaystyle{3}{x}={75}\usepackage{cmbright}\Huge\$ , $\displaystyle{x}={25}\usepackage{cmbright}\Huge\$