Question

помогите пожалуйста
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Answer 1

$\displaystyle\bf\\1)\\\\ay-3y-4a+12=(ay-3y)-(4a-12)=\\\\=y\cdot(a-3)-4\cdot(a-3)=(a-3)\cdot(y-4)\\\\\\2)\\\\9a+9-na-n=(9a+9)-(na+n)=\\\\=9\cdot(a+1)-n\cdot(n+1)=(n+1)\cdot(9-n)\\\\\\3)\\\\mn+m-n-1=(mn+m)-(n+1)=\\\\=m\cdot(n+1)-(n+1)=(n+1)\cdot(m-1)$

$\displaystyle\bf\\4)\\\\ab-ac-2b+2c=(ab-ac)-(2b-2c)=\\\\=a\cdot(b-c)-2\cdot(b-c)=(b-c)\cdot(a-2)\\\\\\5)\\\\a^{3} +a^{2} +a+1=(a^{3} + a^{2} )+(a+1)=\\\\=a^{2} \cdot(a+1)+(a+1)=(a+1)\cdot(a^{2} +1)\\\\\\6)\\\\x^{5} -3x^{3} +4x^{2} -12=(x^{5} -3x^{3} )+(4x^{2} -12)=\\\\=x^{3} \cdot(x^{2} -3)+4\cdot(x^{2} -3)=(x^{2} -3)\cdot(x^{3} +4)$