Question

ptích đa thức thành ntử

a) x³ + x² - 4x - 4

b) x² - 2x - 15

c) x⁴ - 8x

giúp mình với ạ mình cảm ơn nhiều 

Answer 1

`a)x^3+x^2-4x-4=x^2(x+1)-4(x+1)=(x+1)(x^2-4)=(x+1)(x-2)(x+2)`

`b)x^2-2x-15=x^2-5x+3x-15=x(x-5)+3(x-5)=(x-5)(x+3)`

`c)x^4-8x=x(x^3-8)=x(x-2)(x^2+2x+4)`

Answer 2

\(a,x^3+x^2-4x-4=x^2\left(x+1\right)-4\left(x+1\right)=\left(x+1\right)\left(x^2-4\right)=\left(x+1\right)\left(x+2\right)\left(x-2\right)\)\(b,x^2-2x-15=\left(x^2-2x+1\right)-16=\left(x-1\right)^2-16=\left(x-1-4\right)\left(x-1+4\right)=\left(x-5\right)\left(x+3\right)\)\(c,x^4-8x=x\left(x^3-8\right)=x\left(x-2\right)\left(x^2+2x+4\right)\)

Answer 3

a,

= (x3+x2)+(−4x−4)=\(x^2\left(x+1\right)-4\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2-4\right)\)=\(\left(x+1\right)\left(x+2\right)\left(x-2\right)\)

b, ​

\(\left(x^2+3x\right)+\left(-5x-15\right)\) =\(x\left(x+3\right)-5\left(x+3\right)=\left(x+3\right)\left(x-5\right)\)

c, 

= \(x\left(x^3-8\right)=x\left(x-2\right)\left(x^2+2x+2^2\right)\)

= \(x\left(x-2\right)\left(x^2+2x+4\right)\)