Question

Solve :- [4 - (x + y)] [4 + (x + y)]

Answer 1

${\underline{\underline{\huge{\mathfrak{\green{Answer:-}}}}}}$

Hey Mate!!

Let (x+ y) = a.

→ [4 - (x + y)] [4 + (x + y)]

→ (4 - a)(4 + a)

→ 4² - a²                             [∵(a + b)(a - b) = a² - b²]

→ 16 - (x + y)²

→ 16 - (x² + y² + 2xy)         [∵(a + b)² = a² + b² + 2ab]

→ 16 - x² - y² - 2xy