Đáp án:
Giải thích các bước giải:
bài 3:
$a)2\sqrt{x^2}=4$
$⇔2|x|=4$
$⇔|x|=2$
$⇔x=±2$
$b)\sqrt{(1-x)^2}=3$
$⇔|1-x|=3$
$⇔$\(\left[ \begin{array}{l}1-x=3\\1-x=-3\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=-2\\x=4\end{array} \right.\)
$c)\sqrt{(x-3)^2}+2=5$
$⇔\sqrt{(x-3)^2}=3$
$⇔|x-3|=3$
$⇔$\(\left[ \begin{array}{l}x-3=3\\x-3=-3\end{array} \right.\)
$⇔$ \(\left[ \begin{array}{l}x=6\\x=0\end{array} \right.\)
$d)\sqrt{(x^2+4x+4)}=3$
$⇔\sqrt{(x+2)^2}=3$
$⇔|x+2|=3$
$⇔$\(\left[ \begin{array}{l}x+2=3\\x+2=-3\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=1\\x=-5\end{array} \right.\)
$e)\sqrt{(4x^2-4x+1)}=2$
$⇔\sqrt{(2x-1)^2}=2$
$⇔|2x-1|=2$
$⇔$\(\left[ \begin{array}{l}2x-1=2\\2x-1=-2\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=\dfrac{3}{2}\\x=-\dfrac{1}{2}\end{array} \right.\)
