Function or not a function?

Look at attachment. has all info needed. need

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

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 .