Prosessnyaa yahh... madas

U1 + U3 = -5
a + ar^2 = -5
a(1 + r^2) = -5
a = -5/(1 + r^2)

U2 - U3 = 6
ar - ar^2 = 6
a(r - r^2) = 6
-5/(1 + r^2) . (r - r^2) = 6
-5(r - r^2) = 6(1 + r^2)
-5r + 5r^2 = 6 + 6r^2
0 = r^2 + 5r + 6
(r + 2)(r + 3) = 0
r = -2 atau r = -3

U1 + U3 = a + ar^2 = -5

U4 + U6 = ar^3 + ar^5 = r^3 (a + ar^2) = r^3 (-5)
r = -2 => U4 + U6 = (-2)^3 (-5) = -8(-5) = 40
r = -3 => U4 + U6 = (-3)^3 (-5) = (-27)(-5) = 135