\[\boxed{\text{626\ (626).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ a² + 2a + 1 = (a + 1)²\]
\[2)\ x² - 12x + 36 = (x - 6)²\]
\[3)\ y² - 18y + 81 = (y - 9)²\]
\[4)\ 100 - 20c + c^{2} = (10 - c)²\]
\[5)\ a² - 6ab + 9b^{2} = (a - 3b)²\]
\[6)\ 9a² - 30ab + 25b^{2} =\]
\[= (3a - 5b)²\]
\[7)\ b^{4} - 2b^{2}c + c^{2} = (b^{2} - c)²\]
\[8)\ m^{8} + m^{4}n^{2} + \frac{1}{4}n^{4} =\]
\[= \left( m^{4} + \frac{1}{2}n^{2} \right)^{2}\]
\[9)\ 36a²b² - 12ab + 1 =\]
\[= (6ab - 1)²\ \]
\[10)\ x^{4} + 2x² + 1 = (x^{2} + 1)²\]
\[11)\frac{1}{16}x^{4} - 2x^{2}y^{3} + 16y^{6} =\]
\[= \left( \frac{1}{4}x^{2} - 4y^{3} \right)^{2}\]
\[12)\ 0,01a^{8} + 25b^{14} - a^{4}b^{7} =\]
\[= (0,1a^{4} - 5b^{7})²\]