Question

Phân tích đa thức thành nhân tử 

a)\(x^4+4\)

b)\(4x^8+1\)

c)\(x^2-8x-9\)

d)\(x^2+14x+48\)

Answer 1

c) x² - x + 9x - 9

=(x²-x) +  (9x-9)

= x(x-1) + 9(x-1)

= (x-1)(x+9)

Answer 2

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

b) \(4x^8+1=4x^8+4x^4+1-4x^4=\left(2x^4+1\right)^2-4x^4=\left(2x^4-2x^2+1\right)\left(2x^4+2x^2+1\right)\)

d) \(x^2+14x+48=\left(x+7\right)^2-1=\left(x+7+1\right)\left(x+7-1\right)=\left(x+8\right)\left(x+6\right)\)