6. Упростите выражение. a) 3/7 x⁵y⁶ · (-2/3 x⁵y)²;

3/7 x⁵y⁶ ⋅ (-2/3 x⁵y)² = 3/7 x⁵y⁶ ⋅ (4/9 x¹⁰y²) = (3/7 ⋅ 4/9) ⋅ (x⁵ ⋅ x¹⁰) ⋅ (y⁶ ⋅ y²) = (1/7 ⋅ 4/3) ⋅ x¹⁵ ⋅ y⁸ = 4/21 x¹⁵y⁸

Ответ: 4/21 x¹⁵y⁸