1. Given equations:
x + y = 1
y + z = 9
2. In the geometric progression, we substitute \( y = rx \) and \( z = r^2x \):
x + rx = 1
x(1 + r) = 1
3. Solve for \( x \):
x = \frac{1}{1 + r}
4. Substitute \( y = rx \) and \( z = r^2x \) into the second equation:
rx + r^2x = 9
x(r + r^2) = 9
5. Using \( x = \frac{1}{1 + r} \):
\frac{1}{1 + r}(r + r^2) = 9
\frac{r(1 + r)}{1 + r} = 9
r = 9
Therefore, the common ratio \( r \) of the geometric progression is
r = 9