Answer:
Because the kind of compounfds that you try to determine using paper chromatography (organic compounds) are usually not soluble in water. Furthermore, water could react chemically with some of this compounds, because it's a very reactive molecule. You need organic solvents that are mostly inert.
Question 5, x could be either 6 or -1.
Ex: (A) 19.95÷29.95 and you will get your answers
F(x)=3x^2+6x-8
Formula: a=-b/2(a)
a=-6/2(3)=-3
I guess the answer is d)
