Đáp án:
Giải thích các bước giải:
a,$(2x-1)^{3}=-27$
$(2x-1)^{3}=-3^{3}$
=> $2x-1=3$
=> $2x =3+1$
=> $2x =4$
=> $x =4:2$
=> $x =2$
b, $(3x+5)^{2}=9$
TH1: $(3x+5)^{2}=3^{2}$ TH2:$(3x+5)^{2}=-3^{2}$
=>$3x+5 =3$ =>$3x+5 =-3$
=> $3x = 3-5$ => $3x = (-3)-5$
=> $3x =-2$ => $3x =-8$
=> $ x =(-2):3$ => $ x =(-8):3$
=> `x =-2/3` => `x =-8/3`
c,$(5x-25)^{123}=0$
$(5x-25)^{123}=0^{123}$
=>$5x-25=0$
=> $5x=0+25$
=> $5x=25$
=> $x =25:5$
=> $x=5$
