Question

if x-y = 9 and xy = 2 , find the value of (x² + y²)​

Answer 1

x - y = 9

xy = 2

(x - y)² = 9² = 81

x² - xy + y² =81

x² + y² - 2 = 81

x² + y² = 81 - 2

x² + y² = 79