Question

ajutor , repede urgent , dau coroană și 100 de puncte , ex 5 și ex 6, cine nu știe să nu răspundă ​

Answer 1

$\bf a)\,x^2=144 \implies x=\pm \sqrt{144} = \pm \,12$

$\bf \implies x \in \{ 12 ;- 12\}$

$\bf b) \, x^2=256 \implies x= \pm \sqrt{256} = \pm \, 16$

$\bf \implies x \in \{16;-16\}$

$\bf c)\, x^2=400 \implies x= \pm \sqrt{400}=\pm \, 20$

$\bf \implies x \in \{20;-20\}$

$\bf d)\, x^2=576 \implies x= \pm \sqrt{576}= \pm \, 24$

$\bf \implies x \in \{24;-24\}$

$\bf e)\, x^2=625 \implies x= \pm \sqrt{625} = \pm \, 25$

$\bf \implies x \in \{25;-25\}$

$\bf f)\, 3x^2=300 \, |:3 \implies x^2=100$

$\bf \implies x= \pm \sqrt {100} = \pm \, 10 \implies x \in \{10;-10\}$

$\bf g)\,4x^2=324\, |:4 \implies x^2=81$

$\bf \implies x = \pm \sqrt{81}=\pm\, 9 \implies x \in \{9;-9\}$

$\bf h)\, 7x^2=6300\, |:7 \implies x^2=900$

$\bf \implies x = \pm\sqrt{900}= \pm \, 30 \implies x \in \{30;-30\}$

$\bf i) \, 10x^2=490 \, |:10\implies x^2=49$

$\bf \implies x= \pm \sqrt{49} = \pm \, 7 \implies x \in \{7;-7\}$

$\triangle \triangle \triangle$

$\bf a)\, x^2=0 \implies x=0$

$\bf b)\, x^2=-2 (nr\: negativ) \implies x \notin R$

$\bf c)\, x^2=16 \implies x=\pm \sqrt{16}=\pm\, 4$

$\bf \implies x\in \{4;-4\}$

$\bf d)\, 4x^2=64 \, |:4 \implies x^2=16$

$\bf \implies x=\pm \sqrt{16} = \pm \, 4 \implies x \in \{4;-4\}$

$\bf e)\, 3x^2=108 \, |:3 \implies x^2=36$

$\bf \implies x=\pm \sqrt{36}=\pm\, 6 \implies x \in \{6;-6\}$

$\bf f)\,x^2+4=5 \implies x^2=5-4=1$

$\bf \implies x= \pm \sqrt{1} \implies x \in \{1;-1\}$

$\bf g)\, 3x^2+2=1^2+(-1)^2 \implies 3x^2+2=1+1=2$

$\bf \implies 3x^2+2=2_{ /-2} \implies 3x^2=0\, |:3 \implies x=0$

$\bf h)\, x^2+1=(\sqrt{3})^2\implies x^2+1=3_{/-1}$

$\bf \implies x^2=2 \implies x=\pm \sqrt{2} \implies x\in \{\sqrt{2};-\sqrt{2}\}$

$\bf i)\, x^2=\dfrac{4}{25} \implies x = \pm \sqrt{\dfrac{4}{25} }$

$\bf \implies x= \pm \dfrac{2}{5} \implies x\in \bigg\{\dfrac{2}{5} ;-\dfrac{2}{5}\bigg\}$

Bafta! :)

Answer 2

Răspuns:

Explicație pas cu pas: