lean_workbook_plus_13998

The following inequality is true: $\frac{1}{{{{\left( {a + 1} \right)}^2}}} + \frac{1}{{{{\left( {b + 1} \right)}^2}}} + \frac{1}{{{{\left( {c + 1} \right)}^2}}} + \frac{{a + b + c}}{4} \ge \frac{3}{2}$.