Question

Phân tích đa thức thành nhân tử :

a) x - 6\(\sqrt{x}\) + 9

b) x - \(\sqrt{x}\) + \(\dfrac{1}{4}\)

c) 9x - 6\(\sqrt{x}\) + 1

d) x + 5\(\sqrt{x}\) - 14

Answer 1

\(a,x-6\sqrt{x}+9\\ =\sqrt{x^2}-2.3\sqrt{x}+3^2\\ =\left(\sqrt{x}-3\right)^2\\ b,x-\sqrt{x}+\dfrac{1}{4}\\ =\sqrt{x^2}-2.\dfrac{1}{2}\sqrt{x}+\left(\dfrac{1}{2}\right)^2\\ =\left(\sqrt{x}-\dfrac{1}{2}\right)^2\\ c,9x-6\sqrt{x}+1\\ =\left(3\sqrt{x}\right)^2-2.3\sqrt{x}.1+1^2\\ =\left(3\sqrt{x}-1\right)^2\\ d,x+5\sqrt{x}-14\\ =x+7\sqrt{x}-2\sqrt{x}-14\\ =\sqrt{x}\left(\sqrt{x}+7\right)-2\left(\sqrt{x}+7\right)\\ =\left(\sqrt{x}-2\right)\left(\sqrt{x}+7\right)\)