Cho hệ các vecto U={(1,2,n);(0,-1,1-n);(2,3,n+1);(1, 0,2-n)} Tìm số chiều và một cơ sở W của không gian con sinh ra bởi hệ vecto U Tìm tham số k để u= (2,3,k^2+1) là một tổ hợp tuyến tính W, và suy ra [u]w

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

Having a hard time understanding this question (see attachment).

Astocks price gained 3% in april and 5% in may and then lost 4% in june and 1% in july during which month did the stocks price change the most