Question

Can someone try to explain Descartes' Rule of Signs to me?

Answer 1

i can try..its basically counting the sign changes in coefficients

For f(x) the number of sign changes represents the max number of positive zeros
lets say this is n. Then the possible positive zeros are n, n-2, n-4 ... until you get to 0

For f(-x) the number of sign changes represents the max number of negative zeros
lets say this is m. Then the possible positive zeros are m, m-2, m-4 ... until you get to 0

The degree or highest exponent tells you the total number of zeros a function has
any left over zeros must be imaginary, call these i

so any combination of n+m+i must equal the degree.
sometimes it helps to set up a chart

i can do an example if you like

Answer 2

make sense?
need example ?

Answer 3

I'm good, thanks!