Ответ:
Объяснение:
1a)
(x-3)(x-7)-2x(3x-5)= x²-7x-3x+21-6x²+10x= -5x²+21
1b)
4a(a-2)-(a-4)²= 4a²-8a-(a²-8a+16)=4a²-8a-a²+8a-16=3a²-16
1w)
2(m+1)²-4m=2(m²+2m+1)-4m=2m²+4m+2-4m=2m²+2=(2(m²+1)
2a)
x³-9x=x(x²-9)=x(x-3)(x+3)
2b)
-5a²-10ab-5b²=-5(a²+2ab+b²)=-5(a+b)²
3.
(y²-2y)²-y²(y+3)(y-3)+2y(2y²+5)=y^4-4y³+4y²-y²(y²-9)+4y³+10y=
=y^4-4y³+4y²-y^4+9y²+4y³+10y= 13y²+10y=y(13y+10)
4a)
16x^4-81=(4x²)² -9²=(2x²-9)(2x²+9)
4b)
x²-x-y²-y=x²-y²-x-y=(x²-y²)-(x+y)=(x-y)(x+y)-(x+y)=(x+y)(x-y-1)