Question

[nguyenaiphuong2005]

Phân tích các đa thức sau thành nhân tử

a)2x^2 + 6x= 

b) x^4 + 3x^3 + x +3=

c) 64- x^2 - y^2 + 2xy=

  Rứt gọn bt

A= ( x+ 5) ( x+ 1)+ (x-2) (x^2+ 2xx +4)- (x^2+ x-2)

   giúp mình nhanh với

Answer 1

[Nguyễn Hoàng Minh]

\(a,=2x\left(x+3\right)\\ b,=x^3\left(x+3\right)+\left(x+3\right)=\left(x^3+1\right)\left(x+3\right)\\ =\left(x+1\right)\left(x+3\right)\left(x^2-x+1\right)\\ c,=64-\left(x-y\right)^2=\left(8-x+y\right)\left(8+x-y\right)\\ A=x^2+6x+5+x^3-8-x^2-x+2\\ A=x^3+5x-1\)

Answer 2

[Trường Nguyễn Công]

a) 2x²+6x=2x(x+3)
b) x⁴+3x³+x+3=(x⁴+x)+(3x³+3)=x(x³+1)+3(x³+1)=(x+3)(x³+1)
c) 64-x²-y²+2xy=-(x²-2xy+y²)+8²=8-(x+y)²=(8+x+y)(8-x-y)

A= (x+5)(x+1)+(x-2)(x²+2xx+4)-(x²+x-2)
A= x²+6x+5+x³-8-x²-x+2
A= x³+(x²-x²)+(6x-x)+(5-8+2)
A= x³+5x-1