Question

x² + y² - xy = ?
sendo x= 5 e y = -4

Answer 1

5² + (-4)² - (5)(-4) = 25 + 16 + 20 = 61

Answer 2

x = 5; y = - 4

= x² + y² - xy
= 5² + (-4)² - (5).(- 4)
= 25 + 16 + 20
= 41 + 20
= 61