Question

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Answer 1

Ответ:

$1)x^2-2x-3\\\\2)3y^4-7x^2y^2-6x^4\\\\3)b^3+2b+3$

Объяснение:

$1) (x-3)(x+1) = x(x+1) - 3(x+1) = x^2+x-3x-3=x^2-2x-3\\\\2)(2x^2+3y^2)(y^2-3x^2) = 2x^2(y^2-3x^2)+3y^2(y^2-3x^2)=\\\\=2x^2y^2-6x^4+3y^4-9x^2y^2 = 3y^4-7x^2y^2-6x^4\\\\3)(b+1)(b^2-b+3) = b(b^2-b+3)+(b^2-b+3) = b^3-b^2+3b+b^2-b+3=b^3+2b+3$