Question

[Hoàng Thi Thu Hiền]

Tìm x

a, x^15=x

b, 3+2^x-1=24-[4^2-(2^2-1)

^ là dấu nhé!

Mong các bạn sẽ giúp mk

Answer 1

[︵✰ßล∂ ß๏у®]

a, 

\(x^{15}=x\)\(\Leftrightarrow\hept{\begin{cases}x=-1\\x=1\\x=0\end{cases}}\)

b, \(3+2^{\text{x}-1}=24-\text{[}4^2-\left(2^2-1\right)\text{]}\)

\(\Rightarrow3+2^{\text{x}-1}=24-\left(16-3\right)\)

\(\Rightarrow3+2^{\text{x}-1}=24-13\)

\(\Rightarrow2^{\text{x}-1}=11-3\)

\(\Rightarrow2^{\text{x}-1}=8\)

\(\Rightarrow2^{\text{x}-1}=2^3\)

\(\Rightarrow x-1=3\Rightarrow x=3+1=4\)

Vậy x = 4 

Answer 2

[Huỳnh Quang Sang]

a, Tham khảo : Tìm x biết x^15=x - Lê Nhật Minh

b, \(3+2^{x-1}=24-\left[4^2-(2^2-1)\right]\)

\(\Leftrightarrow3+2^{x-1}=24-\left[16-(4-1)\right]\)

\(\Leftrightarrow3+2^{x-1}=24-\left[16-3\right]\)

\(\Leftrightarrow3+2^{x-1}=24-13\)

\(\Leftrightarrow3+2^{x-1}=11\)

\(\Leftrightarrow2^{x-1}=8\)

\(\Leftrightarrow2^{x-1}=2^3\)

\(\Leftrightarrow x-1=3\Leftrightarrow x=4\)

Vậy x = 4