Задание 295

Решение:

• $${\largeа)}\ (5m+7n)(2n+4m)=10mn+14n^2+20m^2+28mn=38mn+14n^2+20m^2$$

• $${\largeб)}\ (12a+b)(3a+5b)=36a^2+3ab+60ab+5b^2=36a^2+63ab+5b^2$$

• $${\largeв)}\ (2x-3y)(2x+3y)=4x^2-6xy+6xy-9y^2=4x^2-9y^2$$

• $${\largeг)}\ (5m-2n)(3n-5m)=15mn-6n^2-25m^2+10mn=25mn-6n^2-25m^2$$

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

• $${\largeе)}\ (-7x-4y)(-5x+7y)=35x^2+20xy-49xy-28y^2=35x^2-29xy-28y^2$$

• $${\largeж)}\ (a^2+b^2)(a^2+b^2)=a^4+a^2b^2+a^2b^2+b^4=a^4+2a^2b^2+b^4$$

• $${\largeз)}\ (mn^3-m^2)(m-1)=m^2n^3-m^3-mn^3+m^2$$

• $${\largeи)}\ (2x^2-y^2)(y^2+2x^3)=2x^2y^2-y^4+4x^5-2x^3y^2$$

• $${\largeк)}\ (xy^2+3a^2)(3xy+a^3)=3x^2y^3+9a^2xy+a^3xy^2+3a^5$$