125 : 5^2 . (x-3) = 3
125 : 25 .(x-3) = 3
5 (x-3) =3
x-3 = 3 : 5
Đề bài sai hay sao ý?
2x -5 = 3
2x = 3+5 =8
x =4
(19 .x+2.5^2 ): 14 = (13-8)^2 - 4^2
19x + 50) : 14 = 25 - 16
(19x+50) : 14 = 9
19x+50 = 3*14 = 126
19x = 126-50 = 76
x = 76 / 19 = 4
\(a\)) \(125:5^2.\left(x-3\right)=3\)
\(5^3:5^2.\left(x-3\right)=3\)
\(5.\left(x-3\right)=3\)
\(5x-15=3\)
\(5x=3+15\)
\(5x=18\)
\(x=\frac{18}{5}\)\(.\)Vậy \(x=\frac{18}{5}\)
\(b\)) \(\left(2x-5\right)^3=27\)
\(\left(2x-5\right)^3=3^3\)
\(\Rightarrow2x-5=3\)
\(\Rightarrow2x=8\)
\(\Rightarrow x=4\)\(.\)Vậy \(x=4\)
\(c\))\(\left(19.x+2.5^2\right):14=\left(13-8\right)^2-4^2\)
\(\left(19.x+2.25\right):14=5^2-16\)
\(\left(19.x+2.25\right):14=25-16\)
\(\left(19.x+50\right):14=9\)
\(19.x+50=126\)
\(19.x=126-50\)
\(19.x=76\)
\(x=76:19\)
\(x=4\)\(.\)Vậy \(x=4\)
