Question

СРОЧНО! РЕШИТЬ УРАВНЕНИЙ СПОСОБОМ ПОДСТАНОВКИ! ДАЮ 30 БАЛЛОВ

Answer 1

$\displaystyle 1)\left \{ {{xy-2y-4x=-5} \atop {y-3x=-2}} \right. \\\\\left \{ {{xy-2y-4x=-5} \atop {y=-2+3x}} \right. \\\\x(-2+3x)-2(-2+3x)-4x=-5\\x=1,x=3\\y=-2+3*1,y=-2+3*3\\y=1,y=7\\(x_1,y_1)=(1,1),(x_2,y_2)=(3,7)\\\\2)\left \{ {{y=x-1} \atop {x^2+y^2-4x-2y=-1}} \right.\\ \\x^2+(x-1)^2-4x-2(x-1)=-1\\x=2+\sqrt{2},x=2-\sqrt{2}\\ y=2+\sqrt{2}-1,y=2-\sqrt{2}-1\\ y=1+\sqrt{2},y=1-\sqrt{2}\\ (x_1,y_1)=(2+\sqrt{2},1+\sqrt{2}),(x_2,y_2)=(2-\sqrt{2},1-\sqrt{2})$