x^2+y^2=5 x^4-y^4=15 решите систему уравнений

Х^2 = а ; х^4 = а^2 y^2 = b ; y^4 = b^2 a + b = 5 a^2 - b^2 = 15 a = 5 - b a^2 = 25 - 10b + b^2 25 - 10b + b^2 - b^2 = 15 25 - 10b = 15 10b = 10 b = 1 a = 5 - 1 = 4 X^2 = a X^2 = 4 X1 = 2 ; X2 = - 2 y^2 = b y^2 = 1 y1 = 1 ; y2 = - 1 Ответ ( 2 ; 1 ) ; ( - 2 ; - 1 )