Question

heeelp ce urmeaza sa fac???

Answer 1

(3x)^2 + 2 * 3 * x * y + y^2 + x^2 - x * y  - y * x  + y^2 = 
= 9 * x^2 + 6 xy + y^2 + x^2 - 2xy + y^2 = 
= 10 x^2 + 4xy + 2y^2 = 2(5 x^2 + 2xy + y^2) = 2(x^2 + (x+y)^2)