Question

[Hoàng Thị Kim Chi]

Tìm n ∈ N ,sao cho;

a) n⁵=32

b) (n-1)⁵=3⁵

c) (n+1)³⁼125

d)  (n-2)¹⁰=1

Answer 1

[ghost river]

a)n⁵ = 32 = 3⁵
\(\Rightarrow\)n=3
( n - 1 )⁵ = 3⁵ 
\(\Rightarrow\)n - 1 = 3
\(\Rightarrow\)n = 3 +1
\(\Rightarrow\)n=4
c)( n + 1 )³ = 125
\(\Rightarrow\)( n + 1 )³ = 5³
\(\Rightarrow\)n + 1 = 5
\(\Rightarrow\)n = 4
d) ( n - 2)¹⁰ = 1
\(\Rightarrow\)( n- 2 )¹⁰ = 1¹⁰ = ( -1)¹⁰
\(\Rightarrow\)\(\orbr{\begin{cases}n-2=1\\n-2=-1\end{cases}\Rightarrow\orbr{\begin{cases}n=3\\n=1\end{cases}}}\)