jika (a + b) : (a - b) = 1 : 5, maka (a^2 - b^2) : ( a^2 + b^2) =

(a + b) : (a - b) = 1 : 5

a + b = 1
a - b = 5
______+
2a = 6
A = 3
Substitusi a = 3 ke persamaan a + b = 1
3 + b = 1
b = -2

(a² - b²) : (a² + b²)
= ((3)² - (-2)²) : ((3)² + (-2)²)
= (9 - 4) : (9 + 4)
= 5 : 13