Помогите решить систему: [tex] \left \{ {{x ^{2}+y ^{2}=20 } \atop {2y-x=0}} ight. [/tex]

x^2 + y^2 = 202y - x = 0====(2y)^2 + y^2 = 20x = 2y====4y^2 +y^2 = 20x = 2y====5y^2 = 20x = 2y====y^2 = 4x = 2y====y_1 = 2x_1 = 2*2====y_2 = -2x_2 = 2*(-2)====y_1 = 2x_1 = 4====y_2 = -2x_2 = -4 Ответ: (4;2) U (-4;-2)