\[\boxed{\text{566}\text{\ (566)}\text{.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[b_{n} = 2n^{2} + 3n\]
\[\textbf{а)}\ b_{5} = 2 \cdot 5² + 3 \cdot 5 = 50 + 15 =\]
\[= 65;\]
\[\textbf{б)}\ b_{10} = 2 \cdot 10² + 3 \cdot 10 =\]
\[= 200 + 30 = 230;\]
\[\textbf{в)}\ b_{50} = 2 \cdot 50² + 3 \cdot 50 = 5150.\]