Question

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Answer 1

Объяснение:

$- 6x(3x + 6y) + 4y(9x - 5y) = - 18x {}^{2} - 36xy + 36xy - 20 {y}^{2} = - 18 {x}^{2} - 20 {y}^{2} \\ - 18( \frac{1}{3} ) {}^{2} - 20 ( \frac{1}{2}) {}^{2} = - 18 \times \frac{1}{9} - 20 \times \frac{1}{4} = - 2 - 5 = - 7$