Решите систему уравнений: а) {x^2+y^2=5     {xy=2   в) {2x^2+3x^2+y^2=0     {x^2-xy-y^2=4   б) {x^2-8xy+16y^2=25      {4y^2-xy=5   г) {x^2-3xy+y^2=-1     {8y^2-3xy=2

{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;   [x+y=-3, [x+y=3;   [y=-3-x, [y=3-x;   [-x(3+x)=2, [x(3-x)=2;   [x^2+3x+2=0, [x^2-3x+2=0; x_1=-2, x_2=-1, x_3=1, x_4=2, y_1=-1, y_2=-2, y_3=2, y_4=1.   {x^2-8xy+16y^2=25, {4y^2-xy=5;   {(x-4y)^2=25, {y(4y-x)=5;   [x-4y=-5, [x-4y=5;   -y(x-4y)=5, [5y=5, [-5y=5; y_1=1, y_2=-1;   [x-4=-5, [x-4*(-1)=5; x_1=-1, x_2=1.