persamaan (2m-4)x^2 + 5x + 2 =0 mempunyai akar-akar real berkebalikan maka nilai m=.... a.-3 b.-1/3 c.1/3 d.3 e.6

x1.x2 = 1
c/a = 1
2/(2m - 4) = 1
2 = 1(2m - 4)
2 = 2m - 4
2+4 = 2m
m = 6/2 = 3

Catatan : ax^2 + bx + c = 0 mempunyai akar
1) saling berlawanan : b = 0
2) saling berkebalikan : a = c

(2m - 4)x^2 + 5x + 2 = 0
a = c
2m - 4 = 2
2m = 6
m = 3