Question

tìm x biết: a) 2ˣ-15=17 b) (7×x-11)=25×5²+200 c)x¹⁰=x

Answer 1

a) \(2^x-15=17\)

\(2^x=17+15=32=2^5\)

\(\Rightarrow x=5\)

Answer 2

b) \(\left(7x-11\right)=25.5^2+200\)

\(7x=825+11=836\)

\(x=\dfrac{836}{7}\)

Answer 3

c) \(x^{10}=x\)

\(x^{10}-x=0\)

\(x\left(x^9-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)