Question

за 65 баллов, два примера.

Answer 1

$\displaystyle\bf\\1)\\\\\frac{1}{9}a^{4} +9b^{2}+2a^{2} b=\Big(\frac{1}{3} a^{2} \Big)^{2}+2\cdot\frac{1}{3} a^{2}\cdot 3+(3b)^{2}=\\\\\\=\Big(\frac{1}{3}a^{2}+3b\Big)^{2}=\Big(\frac{1}{3}a^{2}+3b\Big)\cdot\Big(\frac{1}{3}a^{2}+3b\Big) =\\\\\\=\frac{1}{9}\cdot\Big(a^{2}+9b\Big)\cdot\Big(a^{2}+9b\Big) \\\\2)\\\\-6,4a^{2} y^{4}+0,16a^{4} +64y^{8}=0,16a^{4}-6,4a^{2} y^{4} +64y^{8} =$

$\displaystyle\bf\\=(0,4a^{2})^{2} -2\cdot0,4a^{2}\cdot(8y^{4} )+(8y^{4})^{2}=\\\\\\=(0,4a^{2} -8y^{4} )^{2} =(0,4a^{2} -8y^{4} )\cdot(0,4a^{2} -8y^{4} )=\\\\\\=0,16\cdot(a^{2} -20y^{4} )\cdot(a^{2} -20y^{4} )$