Diketahui X1 dan X2 merupakan akar-akar persamaan 3X² - 5X - 8 = 0 Nilai dari 1/X1 + 1/X2

x1 + x2 = -b/a = -(-5)/3 = 5/3
x1x2 = c/a = -8/3

1/x1 + 1/x2 = (x1 + x2)/(x1x2)
=5/3 / -8/3
=5/3 x -3/8
= - 5/8

PK : ax^2 + bx + c = 0 . akar-akar x1 dan x2, maka x1 + x2 = -b/a = - (-5)/3 = 5/3
x1.x2 = c/a = -8/3
1/x1 + 1/x2 = (x2 + x1)/(x1.x2)
= (5/3)/(-8/3)
= 5/-8
= -5/8