Question

Tìm x \(\in\) N

\(25\le5^{x+1}< 4.5^6\)

Answer 1

T a có:

\(25\le5^{x+1}< 4.5^6\Leftrightarrow5^2\le5^{x+1}< 4.5^6\)

Vì \(x\in N\Rightarrow\)\(2\le x+1< 6\Leftrightarrow1\le x< 5\)

vậy giá trị của x:1,2,3,4.

Answer 2

Ta có :

\(25\le5^{x+1}< 4.5^6\)

\(\Leftrightarrow5^2\le5^{x+1}< 4.5^6\)

Vì \(x\in N\Leftrightarrow2\le x+1< 6\)

\(\Leftrightarrow1\le x< 5\)

\(\Leftrightarrow x\in\left\{1;2;3;4\right\}\)

Vậy ....