Question

Câu 13 

( 2x + 1 )¹⁰ = 49⁵

Answer 1

\(\left(2x+1\right)^{10}=49^5\)

\(\left(2x+1\right)^{10}=\left(7^2\right)^5\)

\(\left(2x+1\right)^{10}=7^{10}\)

\(\left(2x+1\right)^{10}=7^{10}\) hoặc \(\left(2x+1\right)^{10}=\left(-7\right)^{10}\)

\(2x+1=7\) hoặc \(2x+1=-7\)

*) \(2x+1=7\)

\(2x=6\)

\(x=3\)

*) \(2x+1=-7\)

\(2x=-8\)

\(x=-4\)

Vậy \(x=-4;x=3\)

Answer 2

(2x +1)¹⁰ = 49⁵

(2x+1)¹⁰ = (7²)⁵

(2x +1)¹⁰ = 7¹⁰

\(\left[{}\begin{matrix}2x+1=7\\2x+1=-7\end{matrix}\right.\)

\(\left[{}\begin{matrix}2x=6\\2x=-8\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=3\\x=-4\end{matrix}\right.\)