If $$A_{n}X^{n}$$ + $$A_{n-1}X^{n-1}$$ + ... + $$A_{1}X$$ + $$A_{0}$$ = 0 and n>=3, then
Sum of the roots = $$-A_{n-1}/ A_{n}$$
Sum of roots taken two at a time = $$A_{n-2}/ A_{n}$$
Sum of roots taken three at a time = $$-A_{n-3}/ A_{n}$$ and so on
Product of the roots =$$(-1)^nA_0/A_n$$
Ex: For a cubic ax³+bx²+cx+d=0 with roots p,q,r:
p+q+r = −b/a
pq+qr+rp = c/a
pqr = −d/a
