Answer:
Explanation:
x:y:z = 2:7:8 => x = 2/7 y ; z = 7/8y (1)
According to the mean of geometric sequence, we could get :
(y-12) = x.z (2)
based on (1) and (2)
we could get y1 = 28, y2 = 84/11 (3)
based on (3) and (1)
we could get x1 = 8, z1 = 32 ; x2 = 24/11, z2 = 96/11