Question

ALFA dan BETA adalah akar-akar persamaan kuadrat 2xkuadrat - 4x + 3k
-15 =0. bila x1 = 5 +2 x2 maka nilai k adalah... tolong sekalian jalannya ya thanks

Answer 1

2x² - 4x + 3k - 15 = 0
x1 + x2 = -b/a =
5 + 2x2 + x2= 2
3x2 = -3
 x2 = -3/3 = -1

x1x2 = c/a
(5 + 2x2)(x2) = (3k-5)/(2)
(5 -2)(-1) = (3k-5)/(2)
-3(2) = 3k - 5
-6 + 5 = 3k
3k = 1
k = 1/3