Question

Jika x1, x2, dan x3 adalah akar akar persamaan x³-x²-2=0, maka sama dengan

Answer 1

x1.x2.x3 = -d/a = 2

x1+x2+x3 = -b/a = 1

x1.x2+x1.x3+x2.x3 = c/a = 0

1/x1 + 1/x2 + 1/x3 = (x1+x2)/(x1.x2) + 1/x3

                           = ((x1+x2).x3)+x1.x2)/(x1.x2.x3)

                          = (x1.x2+x1.x3+x2.x3)/(2)

1/x1 + 1/x2 + 1/x3 = 0/2 = 0