Question

a) Tìm tập hợp các số tự nhiên n sao cho 50<7^n <2500

b) x- {x-[x-(x+1)]}

Answer 1

\(a)P=\left\{343;2401\right\}\)

\(b)x-\left\{x-\left[x-\left(x+1\right)\right]\right\}=x-\left\{x-\left[x-x-1\right]\right\}\)

\(=x-\left\{x-x+x+1\right\}\)

\(=x-x+x-x-1=-1\)

Answer 2

a) \(n=\left\{3,4\right\}\)

b)\(x-\left\{x-\left[x-\left(x-1\right)\right]\right\}\)

\(=x-\left[x-\left(x-x+1\right)\right]\)

\(=x-\left(x-1\right)\)

\(=x-x-1=-1\)

_Tần vũ_