Решить задания подробно

$(a + 3) ^{2} \\ (a + b )^{2} = a ^{2} + 2ab + {b}^{2} \\ {a}^{2} + 2a \times 3 + {3}^{2} \\ {a}^{2} + 6a + {3}^{2} \\ {a}^{2} + 6a + 9$

$(b + c) ^{2} = {b}^{2} + 2bc + {c}^{2}$

$(5 + n) ^{2} = 25 + 10n + {n}^{2} \\ {n}^{2} + 10n + 25$

$(x + 6) ^{2} = {x}^{2} + 2x \times 6 + {6}^{2} \\ {x}^{2} + 12x + {6}^{2} \\ {x}^{2} + 12x + 36$

$(0.8a + 50b) ^{2} = ( \frac{4}{5} a + 50b) ^{2} \\ \frac{16}{25} {a}^{2} + 80ab + 2500 {b}^{2}$

$( \frac{1}{4} {x}^{3} ) ^{2} + 2 \times \frac{1}{4} x ^{3} \times 2 {y}^{2} + (2 {y}^{2} ) ^{2} \\ \frac{1}{16} {x}^{6} + 2 \times \frac{1}{4} {x}^{3} \times 2 {y}^{2} + (2 {y}^{2} ) ^{2} \\ \frac{1}{16} {x}^{6} + {x}^{3} {y}^{2} + 4 {y}^{4}$