Jika (a+b) : (a-b) = 1 : 5 maka (a²-b²) : (a²+b²) = .....

A + b = 1
a - b = 5
------------ +
2a = 6
a = 3

a - b = 5
3 - b = 5
b = 3 - 5 = -2

(a² - b²) : (a²+ b²)
(3² - (-2)²) : (3² + (-2)²)
(9 - 4) : (9 + 4)
5 : 13