Question

Піднесіть до квадрата: (7 - 3x)2 - (2x - Зу)2 =​

Answer 1

Ответ:

${(7 - 3x)}^{2} - {(2x - 3y)}^{2} = {7}^{2} - 2 \times 7 \times 3x + {( - 3x)}^{2} - ( {(2x)}^{2} - 2 \times 2x \times 3y + {( - 3y)}^{2} = 49 - 42x + 9 {x}^{2} - (4 {x}^{2} - 12xy + 9 {y}^{2} ) = 49 - 42x + 9 {x}^{2} - 4 {x}^{2} + 12xy - 9 {y}^{2} = 5 {x}^{2} + 12xy - 9 {y}^{2} - 42x + 49$