Verified answer

20c²-45=5*(4c²-9)=5*(2c-3)(2c+3)

7m²+14mn+7n²=7*(m²+2mn+n²)=7*(m+n)²

-3xy-24y-9x-72=-(3xy+9x)-(24y+72)=-3x(y+3)-24(y+3)=(y+3)(-3x-24)=

-3*(y+3)(x+8)

a²-b²-b-a=(a-b)(a+b)-(a+b)=(a+b)(a-b-1)

x³-x²z+x²-xz=(x³+x²)-(x²z+xz)=x²(x+1)-xz(x+1)=(x+1)(x²-xz)=x(x+1)(x-z)

Verified answer

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Разложить данные многочлены на множители :

1)

20c² - 45=5(4c²-9)=5( (2c)² -3²) =5(2c-3)(2c+3) ;

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2)

7m² + 14mn + 7n²=7(m² + 2m*n + n²)=7(m + n)² ;

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3)

- 3x y- 24y - 9x - 72= - 3y(x + 8) - 9(x + 8)= - 3(x + 8)(y + 3) ;

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4)

a² -  b ² -  b -  a= (a² - b²) - (a + b) = (a - b)(a + b) - (a + b)=(a + b)(a - b -1)

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5)

x³ - x²z + x²- xz = x²(x - z) +x(x - z)=(x - z)(x² + x)=*x(x+1)(x - z) .