Question

Решите уравнение:
а) {x^2+8xy+16y^2=25
4y^2+xy=5

Answer 1

{x^2+y^2=5,

{xy=2;

 

x^2+2xy+y^2-2xy=5,

(x+y)^2-2xy=5;

(x+y)^2-2*2=5;

(x+y)^2=9;