giải phương trình a, 2 $\sqrt[]{x+3}$ + $\sqrt[]{9x+27}$ =5 -$\frac{1}{3}$$\sqrt[]{x+3}$ b, $\sqrt[]{x-2\sqrt[]{x-1}}$ =2

By Valentina

giải phương trình
a, 2 $\sqrt[]{x+3}$ + $\sqrt[]{9x+27}$ =5 -$\frac{1}{3}$$\sqrt[]{x+3}$
b, $\sqrt[]{x-2\sqrt[]{x-1}}$ =2

0 bình luận về “giải phương trình a, 2 $\sqrt[]{x+3}$ + $\sqrt[]{9x+27}$ =5 -$\frac{1}{3}$$\sqrt[]{x+3}$ b, $\sqrt[]{x-2\sqrt[]{x-1}}$ =2”

  1. $@phamnhuy6a1$
    $@gaumatyuki$

    $a)$ $2$ $\sqrt[]{x+3}$ + $\sqrt[]{9x+27}$ = $5-$ $1/3$ $\sqrt[]{x+3}$ 

    ⇔ $2$ $\sqrt[]{x+3}$ + $\sqrt[]{3².(x+3)}$+ $1/3$ $\sqrt[]{x+3}$ = $5$ 

    ⇔ $2$ $\sqrt[]{x+3}$ + $3$ $\sqrt[]{x+3}$+ $1/3$ $\sqrt[]{x+3}$ = $5$

    ⇔ $(2+3+1/3)$. $\sqrt[]{x+3}$ =$5$

    ⇔ $16/3$. $\sqrt[]{x+3}$ =$5$

    ⇔ $\sqrt[]{x+3}$ = $15/16$

    ⇔ $x+3=225/256$

    ⇔$x= -543/256$

    $Vậy$ $pt$ $có$ $nghiệm$ $x=-543/256$

    $b)$ $\sqrt[]{x-2\sqrt[]{x-1}}$ $=2$

    ⇔ $\sqrt[]{(x-1)-2\sqrt[]{x-1}+1}$ $=2$

    ⇔ $\sqrt[]{(\sqrt[]{x-1}-1)²}$ $=2$

    ⇔$\sqrt[]{x-1}$ $-1)²$ $=2$

    ⇔ $\sqrt[]{x-1}$  $-1=2$
    ⇔ $\sqrt[]{x-1}$ $=1$

    ⇔ $x-1=1$

    ⇔$x=2$

    $Vậy$ $pt$ $có$ $nghiệm$ $x=2$

    $Chúc$ $bạn$ $học$ $tốt!$

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