Question

Phân tích các đa (tách hạng tử thành nhiều hạng tử)

a)x³ - 7x - 6

b) x³ - 5x² - 14x

Answer 1

a)

\(x^3-7x-6=x^3+1-7x-7\)

= \(\left(x+1\right)\left(x^2-x+1\right)-7\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2-x+1-7\right)\)

= \(\left(x+1\right)\left(x^2-x-6\right)\)

b)

\(x^3-5x^2-14x=x^3+2x^2-7x^2-14x\)

= \(x^2\left(x+2\right)-7x\left(x+2\right)\)

= \(\left(x^2-7x\right)\left(x+2\right)\)

= \(x\left(x-7\right)\left(x+2\right)\)

Answer 2

a,x^3 -x-6x-6 = x(x^2 -1)-6(x+1)= x(x-1)(x+1)-6(x+1)=(x+1)(X^2-x-6)=(x+1)(x^2+2x-3x-6)=(x+1)(x(x+2)-3(x+2))=(x+1)(x+2)(x-3)

b,x(x^2-5x-14)=x(x^2+2x-7x-14)=x(x(x+2)-7(x+2))=x(x+2)(x-7)