Question

ai làm giúp em với

A=\(4\sqrt{x}-\frac{\left(x+6\sqrt{x}+9\right)\left(\sqrt{x}-3\right)}{x-9}\)với 0<x khác 9

B=\(\frac{\sqrt{9x^2+12x+4}}{3x+2}\)với x khác \(-\frac{2}{3}\)

Answer 1

\(A=4\sqrt{x}-\frac{\left(\sqrt{x}+3\right)^2\left(\sqrt{x}-3\right)}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\)

\(=4\sqrt{x}-\left(\sqrt{x}+3\right)\)

\(=3\sqrt{x}-3\)

\(B=\frac{\sqrt{\left(3x+2\right)^2}}{3x+2}=\frac{|3x+2|}{3x+2}\)

\(TH1:3x+2>0\Rightarrow B=1\)

\(TH2:3x+2< 0\Rightarrow B=-1\)

Answer 2

A <=> 4√x - [ ( (√x )^2 + 2√x3+ 3^2)*( √x -3)]/ (x-9)

<=> 4√x - [(√x+3)^2×(√x-3)]/( x-9)

<=> 4√x - [(√x+3)*(x-9)]/(x-9)

<=> 4√x - √x -3

<=> 3√x -3

b, <=> √[(3*x) ^2+2*3x*2+2^2]/(3x+2)

<=> √[( 3x+2)^2] /(3x+2) 

<=> (3x+2)/(3x+2) = 1