3.
5)c³+27b³=c³+(3b)³=(c+3b)(c²-3bc+9b²)
3)-5x²+10xn-5n²=-5(x²-2xn+n)=-5(x-1)²=-5(x-1)(x-1)
5)a^4-64=(a^2-8^2)=(a-8)(a+8)
6)x²y-64y²=y(x²-64y²)=y(x-8y)(x+8y)
4)4ab-28b+8a-56=4ab+8a-28b-56=4a(b+2)-28(b+2)=(b+2)(4a-28)
2.
b(b+2)(b-2)-(b-3)(b²+3b+9)=b²-4-(b³-27)=b²-b³+23
5.
5)x³-8x²+16x=x(x²-8x+16)=x(x-4)²=x(x-4)(x-4)
3)ab^5-b^5-ab³+b³=(ab^5-ab³-b^5+b³)=ab³(b²-1)-b³(b²-1)=
=(b²-1)(ab³-b³)=b³(a-1)(b²-1)=b³(a-1)(b-1)(b+1)
2)9m²+6mn+n²-25=(3m+n)²-25=(3m+n-5)(3m+n+5)
4.
1)4x³-16x=0
4x(x²-4)=0
4x(x-2)(x+2)=0
4x=0 , x-2=0 , x+2=0
X1=0 x2=2 x3=-2
2)49x³+14x²+x=0
X(49x²+14x+1)=0
49x²+14x+1=0
Δ=196-196=0
X1=-b/2a=-14/2*49=-1/7
3)y^3-5y^2-y+5=0
y²(y-5)-(y-5)=0
(y-5)(y²-1)=0
(y-5)(y-1)(y+1)=0
y-5 = 0 , y-1=0 , y+1=0
y1=5 y2=1 , y3=-1