$|x+3|=6$
=> $x+ 3= 6 hoặc x+3= -6$
$x= 3 hoặc x= -9$
$2x^2 -72= 0$
=>$2x^2= 72 => x^2= \dfrac{72}{2} = 36$
=> $x^2 = 6^2$
=> $x= 6 hoặc x= -6$
$5^{x+1}= 125$
=>$5^{x+1}= 5^3$
=>$x+1= 3$
=> $x=2$
$4(3x-4)-2=18$
=>$4(3x-4)= 20$
=>$3x-4= 5$ => $3x= 9$ => $x=3$
$\dfrac{1}{3} + \dfrac{2}{5}(x+1)=1$
=> $\dfrac{2}{5}(x+1)= 1-\dfrac{1}{3}= \dfrac{2}{3}$
=> $x+1= \dfrac{2}{3}:\dfrac{2}{5}= \dfrac{5}{3}$
=> $x= \dfrac{5}{3}-1= \dfrac{2}{3}$
