A^2-B^2=21 dan A-B=3. Tentukan A^5-B^5=

a² + b² = (a + b)²

(a + b)² = a² + 2ab + b²

(a + b)² = a² + b² + 2(2)

(a + b)² = 5 + 2(2)

(a + b)² = 9

a + b = 3