b, bq, bq² = 18;
0 < q < 1
b = 18/q²
18/q = 18/q² + d
d = 18/q - 18/q²
18/q² + 2d = 10
18/q² + 36/q - 36/q² = 10
18/q - 9/q² = 5
5q² - 18q + 9 = 0
D = 324 - 180 = 144 = 12²
q = (18 - 12)/10 = 0,6
b = 18/q² = 1800/36 = 50
ответ: 50
b, bq, bq² = 18;
0 < q < 1
b = 18/q²
18/q = 18/q² + d
d = 18/q - 18/q²
18/q² + 2d = 10
18/q² + 36/q - 36/q² = 10
18/q - 9/q² = 5
5q² - 18q + 9 = 0
D = 324 - 180 = 144 = 12²
q = (18 - 12)/10 = 0,6
b = 18/q² = 1800/36 = 50
ответ: 50