Answer:
y² + 2 x y
Step-by-step explanation:
Given polynomials
x² + 3x y -y² and x² + 5xy
The subtract x² + 3x y -y² from x² + 5xy
x² + 5xy - ( x² + 3x y -y²)
⇒ x² + 5xy -x² - 3xy +y²
⇒ 2 x y + y²
