Question

Bài 1; Tìm n ∈ Z;

a.7ⁿ =49

b,5ⁿ=625

c,4ⁿ=64

d,2ⁿ⁼¹²⁸

Answer 1

a)\(49=7^2\Rightarrow n=7\)

b)\(625=5^4\Rightarrow n=4\)

c)\(64=4^3\Rightarrow n=3\)

d)\(128=2^7\Rightarrow n=7\)

Answer 2

a) Ta có: 49 = 7 . 7 = 7²

=> x = 2

b) Ta có 625 = 5 . 5 . 5 . 5 = 5⁴

=> x = 4

c) Ta có: 64 = 4 . 4 . 4 = 4³

=> x = 3

d) Ta có: 128 = 2 . 2 . 2 . 2 . 2 . 2 . 2 = 2⁷

=> x = 7