Answer:
a² + b² = 20
Step-by-step explanation:
Given
(a - b) = 4 ← square both sides
(a - b)² = 4²
a² - 2ab + b² = 16 ← substitute ab = 2
a² - 2(2) + b² = 16
a² - 4 + b² = 16 ( add 4 to both sides )
