Is 2y=-8x a direct variation

Can someone me and plz do the problem

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

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 .