1/ Tim x
25 - [ x - 2/5 ] : 1/2 = 1
K
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Những câu hỏi liên quan
T
0
BT
2
KT
21 tháng 7 2018
\(x^2-2x+1=25\)
\(\Leftrightarrow\)\(\left(x+1\right)^2=25\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x+1=5\\x+1=-5\end{cases}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x=4\\x=-6\end{cases}}\)
Vậy...
\(3\left(x-1\right)^2-3x\left(x-5\right)=1\)
\(\Leftrightarrow\)\(3\left(x^2-2x+1\right)-\left(3x^2-15x\right)=1\)
\(\Leftrightarrow\)\(3x^2-6x+3-3x^2+15x=1\)
\(\Leftrightarrow\)\(9x=-2\)
\(\Leftrightarrow\)\(x=-\frac{2}{9}\)
Vậy....
BT
2
KT
21 tháng 7 2018
\(x^2-2x+1=25\)
\(\Leftrightarrow\)\(\left(x-1\right)^2=25\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x-1=5\\x-1=-5\end{cases}}\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}x=6\\x=-4\end{cases}}\)
Vậy....
b) \(3\left(x-1\right)^2-3x\left(x-5\right)=1\)
\(\Leftrightarrow\)\(3x^2-6x+3-3x^2+15x=1\)
\(\Leftrightarrow\)\(9x=-2\)
\(\Leftrightarrow\)\(x=-\frac{2}{9}\)
Vậy...
29 tháng 7 2019
Tìm x thuoc z:
1) \(26-\left|x+9\right|=-13\)
\(\Leftrightarrow\left|x+9\right|=26-\left(-13\right)\)
\(\Leftrightarrow\left|x+9\right|=39\)
\(\Leftrightarrow\left[{}\begin{matrix}x+9=39\\x+9=-39\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=39-9=30\\x=-39-9=-48\end{matrix}\right.\)
Vậy: \(x\in\left\{30;-48\right\}\)
2) \(\left|x+7\right|-13=25\)
\(\Leftrightarrow\left|x+7\right|=25+13=38\)
\(\Leftrightarrow x+7\in\left\{38;-38\right\}\)
\(\Leftrightarrow x\in\left\{31;-45\right\}\)
Vậy:.................
tim x biet
\(1)123-3.\left(x+4\right)=23\)
\(\Leftrightarrow3\left(x+4\right)=123-23\)
\(\Leftrightarrow3\left(x+4\right)=100\)
\(\Leftrightarrow x+4=\frac{100}{3}\)
\(\Leftrightarrow x=\frac{100}{3}-4=\frac{100-12}{3}=\frac{88}{3}\)
Vậy:................
2) Tương tự
NT
0
MV
15 tháng 5 2017
1)
\(2^{x-1}=16\\ 2^{x-1}=2^4\\ \Rightarrow x-1=4\\ x=4+1\\ x=5\)
5)
\(\left(x-1\right)^2=25\Rightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\)
6)
\(\left|2x-1\right|=5\Rightarrow\left[{}\begin{matrix}2x-1=5\\2x-1=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)
HC
15 tháng 5 2017
5) (x-1)2 = 25
(x-1)2 = 52
x-1 = 5
x = 5+1
x = 6
6) \(\left|2x-1\right|=5 \)
\(TH1:\) \(2x-1=5\)
\(\Leftrightarrow2x=5+1\)
\(\Leftrightarrow2x=6\)
\(\Leftrightarrow x=6:2\)
\(\Leftrightarrow x=3\)
\(TH2:2x-1=-5\)
\(\Leftrightarrow2x=-5+1\)
\(\Leftrightarrow2x=-4\)
\(\Leftrightarrow x=-4:2\)
\(\Leftrightarrow x=-2\)
Vậy x = 3 hoặc x = -2.
Tick nha!
25 - ( x - \(\frac{2}{5}\) ) : \(\frac{1}{2}\) = 1
( x - \(\frac{2}{5}\) ) : \(\frac{1}{2}\) =25-1
( x - \(\frac{2}{5}\) ) : \(\frac{1}{2}\) =24
( x - \(\frac{2}{5}\) ) =24x \(\frac{1}{2}\)
( x - \(\frac{2}{5}\) ) = 12
x =12 + \(\frac{2}{5}\)
x =\(\frac{62}{5}\)