\[10a^{2}\]
\[a = 9:\]
\[10 \cdot 9^{2} = 10 \cdot 81 = 810.\]
\[a = - \frac{1}{2}:\]
\[10 \cdot \left( - \frac{1}{2} \right)^{2} = 10 \cdot \left( \frac{1}{2} \right)^{2} =\]
\[= 10 \cdot \frac{1}{2^{2}} = 10 \cdot \frac{1}{4} = \frac{10}{4} = \frac{5}{2} = 2,5.\]
\[a = - 1,2:\]
\[10 \cdot ( - 1,2)^{2} = 10 \cdot {1,2}^{2} =\]
\[= 10 \cdot 1,44 = 14,4.\]