\[\boxed{\text{985.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ b^{2} + 10b + 25 = (b + 5)^{2} =\]
\[= (b + 5)(b + 5)\]
\[\textbf{б)}\ c² - 8c + 16 = (c - 4)² =\]
\[= (c - 4)(c - 4)\]
\[\textbf{в)}\ 16x² - 8x + 1 = (4x - 1)² =\]
\[= (4x - 1)(4x - 1)\]
\[\textbf{г)}\ 4c² + 12c + 9 = (2c + 3)² =\]
\[= (2c + 3)(2c + 3)\]
\[\textbf{д)}\ x^{4} + 2x²y + y² =\]
\[= (x^{2} + y)² = (x^{2} + 1)(x^{2} + y)\]
\[\textbf{е)}\ a^{6} - 6a^{3}b^{2} + 9b^{4} =\]
\[= \left( a^{3} - 3b^{2} \right)^{2} =\]
\[= (a^{3} - 3b^{2})(a^{3} - 3b^{2})\]