Maths  Geometric Progression
posted by Anonymous .
Find the value of x for which the numbers x+1, x+3, x+7, are in geometric progression.

If in a GP, then
(x+3)/(x+1) = (x+7)/(x+3)
x^2 + 6x + 9 = x^2 + 8x + 7
2x = 2
x=1
check:
numbers would be 2 , 4, 8 which are in GP with a common ratio of 2