Câu hỏi của Trần Quang Hiếu

Question

Bai 2: Tim x biet:

1) 2$^{x-1}=16$                      5) (x-1)$^2$=25                    6) $\left|2x-1\right|=5$

Mới vô · Accepted Answer

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)

$\left|2x-1\right|=5\Rightarrow\left[{}\begin{matrix}2x-1=5\2x-1=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\x=-2\end{matrix}\right.$Câu trả lời: 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)

$\left|2x-1\right|=5\Rightarrow\left[{}\begin{matrix}2x-1=5\2x-1=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\x=-2\end{matrix}\right.$

Huỳnh Châu · Answer

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!Câu trả lời: 5) (x-1)2 = 25