2. (5x+7y) (2x – 3y) = 10x² + xy – xy – 21y² = = 10x2 – xy – 21y2.

Решим уравнение.

1. (5x + 7y) (2x – 3y) = 10x² + 14xy - 15xy – 21y² = 10x² – xy – 21y².

Заполним пропуски.

1. (5x + 7y) (2x – 3y) = 10x² + 14xy – 15xy – 21y² = = 10x² – xy – 21y².

Ответ: 14; 15.