Задание 279

Решение:

• $${\largeа)}\ (-2)(x+y)=(-2)x-2y$$

• $${\largeб)}\ (7+3y-x^2y)(-2xy)=(-14)xy-6xy^2+2x^3y^2$$

• $${\largeв)}\ 3ab(a^2-2a+1)=3a^3b-6a^2b+3ab$$

• $${\largeг)}\ 2a(x+y)=2ax+2ay$$

• $${\largeд)}\ (x^2+2xy+y^2)(-12xy^3)=(-12)x^3y^3-24x^2y^4-12xy^5$$

• $${\largeе)}\ 21a^2b^5(a^3-4ab^2-b^2)=21a^5b^5-84a^3b^7-21a^2b^7$$

• $${\largeж)}\ (-abc)(ab+ac+bc)={-}a^2b^2c-a^2bc^2-ab^2c^2$$

• $${\largeз)}\ {-}ac(a+2c)={-}a^2c-2ac^2$$