Đáp án:
Giải thích các bước giải:
1)$|5x-3|-x=7$
$⇔|5x-3| =x+7$
$⇔\left[ \begin{array}{l}5x-3=x+7\\5x-3=-x-7\end{array} \right. $
$⇔\left[ \begin{array}{l}4x=10\\6x=-4\end{array} \right. $
$⇔\left[ \begin{array}{l}x=\frac{5}{2}\\x=-\frac{2}{3}\end{array} \right. $
b)$|2x+3|-4x<9$
TH1: $2x+3-4x<9$
⇔$-2x <6$
$⇔x >-3$
TH2: $-2x-3-4x <9$
$⇔-6x <12$
$⇔x>2$
3)$16^x :8 =2$
$⇔16^x =2.8$
$⇔16^x =16^1$
$⇔x =1$
