Выполните умножение многочлена на многочлен: (x+y)(2x-3y)= (2x-7)(3x+6)= (-4,5y+2,3)(1,2y-8,9)= (1,8x-2,5)(0,2x+3,4)=

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Accepted Answer

(x+y)(2x-3y)
\(x \cdot 2x + x \cdot (-3y) + y \cdot 2x + y \cdot (-3y) = 2x^2 - 3xy + 2xy - 3y^2 = 2x^2 - xy - 3y^2\)
(2x-7)(3x+6)
\(2x \cdot 3x + 2x \cdot 6 - 7 \cdot 3x - 7 \cdot 6 = 6x^2 + 12x - 21x - 42 = 6x^2 - 9x - 42\)
(-4,5y+2,3)(1,2y-8,9)
\(-4.5y \cdot 1.2y - 4.5y \cdot (-8.9) + 2.3 \cdot 1.2y + 2.3 \cdot (-8.9) = -5.4y^2 + 40.05y + 2.76y - 20.47 = -5.4y^2 + 42.81y - 20.47\)
(1,8x-2,5)(0,2x+3,4)
\(1.8x \cdot 0.2x + 1.8x \cdot 3.4 - 2.5 \cdot 0.2x - 2.5 \cdot 3.4 = 0.36x^2 + 6.12x - 0.5x - 8.5 = 0.36x^2 + 5.62x - 8.5\)

Ответ: 2x² - xy - 3y²; 6x² - 9x - 42; -5.4y² + 42.81y - 20.47; 0.36x² + 5.62x - 8.5.