pliss di bantu ya yg satu ini,

x1 + x2 = -b/a
x1 . x2 = c/a = -2/a

1/x1 + 1/x2 = -4
(x1 + x2)/(x1 . x2) = -4
(-b/a) / (-2/a) = -4
(-b/-2) = -4
b/2 = -4
b = -4×2 = -8

x1 = -½.x2
-2x1 = x2

x1 + x2 = -b/a
x1 + (-2x1) = -8/a
-x1 = -8/a
x1 = 8/a

x1 . x2 = -2/a
x1 . (-2x1) = -2/a
-2(x1)² = -2/
(x1)² = -2/(-2)a
(x1)² = 1/a
(8/a)² = 1/a
64/a² = 1/a
64 = a²/a
64 = a

a + b = 64 + (-8) = 56