Question

Bài 1: Phân tích đa thức thành nhân tử

a) √3 - √3 +√15- 2√5

b)x-5

c) x√x - 1

d) x√x + 1

Answer 1

b)x-5=\(\left(\sqrt{x}\right)^2-\left(\sqrt{5}\right)^2\) =\(\left(\sqrt{x}-\sqrt{5}\right)\left(\sqrt{x}+\sqrt{5}\right)\)

c)\(x\sqrt{x}-1=\left(\sqrt{x}\right)^3-1\)

=\(\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)\)

d)\(x\sqrt{x}+1=\left(\sqrt{x}\right)^3+1\)

=\(\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)\)

a)\(\sqrt{15}-2\sqrt{5}=\sqrt{3}\sqrt{5}-2\sqrt{5}\)

=\(\sqrt{5}.\left(\sqrt{3}-2\right)\)