Question

Tìm x, y biết:

a,4^x=2^x+1

b,16=(x-1)⁴

c,x²+2^y=25

Answer 1

a/ \(4^x=2^{x+1}\)

\(\Leftrightarrow\left(2^2\right)^x=2^{x+1}\)

\(\Leftrightarrow2^{2x}=2^{x+1}\)

\(\Leftrightarrow2x=x+1\)

\(\Leftrightarrow2x-x=1\)

\(\Leftrightarrow x=1\left(tm\right)\)

Vậy .....

b/ \(16=\left(x-1\right)^4\)

\(\Leftrightarrow\left[{}\begin{matrix}\left(x-1\right)^4=4^4\\\left(x-1\right)^4=\left(-4\right)^4\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=4\\x-1=-4\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\)

Vậy ...

c/ bí

Answer 2

b) 16 = ( x - 1 )⁴

2⁴ = ( x - 1 )⁴

\(\Rightarrow\) 2 = x - 1

\(\Leftrightarrow\) x - 1 = 2

x = 2 + 1

x = 3