Question

1. tim n

a,5ⁿ=625

b.12ⁿ=144

c.(n-2)²=(n-2)⁴

Answer 1

a. \(5^n=625\)

\(\Rightarrow5^n=5^4\)

\(\Rightarrow n=4\)

Vậy.....

b. \(12^n=144\)

\(\Rightarrow12^n=12^2\)

\(\Rightarrow n=2\)

Vậy........

Answer 2

a) 5ⁿ = 625

\(\Rightarrow\) 5ⁿ = 5⁴

\(\Rightarrow\) n = 4

Answer 3

a,5ⁿ=625

5ⁿ=5⁴

=>n=4

b,12ⁿ=144

12ⁿ=12²

=>n=2

Answer 4

a) 5ⁿ=625

=> 5ⁿ=5⁴

=> n=4

b) 12ⁿ=144

=> 12ⁿ=12²

=> n=2

c) (n-2)²=(n-2)⁴

=> (n-2)²-(n-2)⁴=0

=> (n-2)²[1-(n-2)²]=0

=> \(\left[{}\begin{matrix}\left(n-2\right)^2=0\\1-\left(n-2\right)^2=0\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}n-2=0\Rightarrow n=2\\\left(n-2\right)^2=1\Rightarrow n-2=\pm1\Rightarrow\left[{}\begin{matrix}n-2=1\Rightarrow n=3\\n-2=-1\Rightarrow n=1\end{matrix}\right.\end{matrix}\right.\)

vay n\(\in\) { 1;2;3}

=>