a)$(x+5)^{3}$$=$$-64$
⇒$(x+5)^{3}$$=$$(-4)^{3}$
⇒$x+5=-4$
⇒$x=(-4)-5$
⇒$x=-9$
Vậy $x=-9$
b)$(2x-3)^{2}$$=9$
⇒ $(2x-3)^{2}$$=$$3^{2}$ hoặc $(2x-3)^{2}$$=$$(-3)^{2}$
⇒\(\left[ \begin{array}{l}2x-3=3\\2x-3=-3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=3+3\\2x=-3+3\end{array} \right.\)
⇒\(\left[ \begin{array}{l}2x=6\\2x=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=3\\x=0\end{array} \right.\)
Vậy \(\left[ \begin{array}{l}x=3\\x=0\end{array} \right.\)
Chúc bn hok tốt!!
