Question

Rút gọn biểu thức:

\(A=\dfrac{x-5\sqrt{x}+6}{\sqrt{x}-3}\) (với x ≥ 0; x ≠ 9 )

mọi người giúp mk nha!

Answer 1

\(A=\dfrac{x-5\sqrt{x}+6}{\sqrt{x}-3}=\dfrac{x-2\sqrt{x}-3\sqrt{x}+6}{\sqrt{x}-3}\)

\(=\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)-3\left(\sqrt{x}-2\right)}{\sqrt{x}-3}\)

\(=\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}-3\right)}{\sqrt{x}-3}=\sqrt{x}-2\)

Answer 2

A=B/C

B=x-5√x+6=(√x-2)(√x-3)

{ vi et (x1+x2=-5; x1.x2=6}

B=(√x-2).C

C≠0=> x≠9

kl

x≠9; A=√x-2