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Решите задачу:

$(2 {x}^{5} {y}^{7} ) {}^{3} \div ( {x}^{14} y {}^{20} ) - (3x {y}^{5} ) {}^{3} \div (x {}^{2} y {}^{14} ) = \\ = \frac{ (2 {x}^{5} {y}^{7} ) {}^{3}}{{x}^{14} y {}^{20}} - \frac{(3x {y}^{5} ) {}^{3}}{x {}^{2} y {}^{14}} = \frac{8 {x}^{15}y {}^{21} }{{ x}^{14} y {}^{20}} - \frac{27 {x}^{3} {y}^{15} }{ {x}^{2} {y}^{14} } = \\ = \frac{8xy}{1} - \frac{27xy}{1} = 8xy - 27xy = - 19xy$