Question

(x+y-3)(x+y+3) Simplify by applying standard formula​

Answer 1

Answer:

$(x+y-3)(x+y+3)= (x + y)^2 -9$

Step-by-step explanation:

(x+y-3)(x+y+3)

= x(x+y+3) + y (x+y+3) - 3 (x+y+3)

$= x^2 + xy + 3x + xy + y^2 + 3y - 3x -3y - 9\\= x^2+ y^2 + xy + xy + 3x - 3x + 3y -3y - 9\\= x^2+ y^2 + 2xy - 9\\= (x + y)^2 -9$