Answer:
a : b = 25 : 9
Step-by-step explanation:
(3a - 5b) : (3a + 5b) = 1 : 4
Product of extremes = product of means
(3a - 5b) *4 = (3a +5b) * 1 {Distributive property}
3a * 4 - 5b*4 = 3a + 5b
12a - 20b = 3a + 5b
Add 20b to both sides
12a = 3a + 5b + 20b
12a = 3a + 25b
Subtract 3a from both sides
12a - 3a = 25b
9a = 25b
a:b = 25 : 9