Question

Решите систему уравнений (70баллов) см. фото ниже, (любым способом, но желательно подстановкой)

Answer 1

$1) left { {x-2y=0{} atop {x^2=2y+2x-2}} right. left { {{x=2y} atop {(2y)^2-2y-2(2y)+2=0,}} right. left { {{x=2y} atop 4y^2-6y+2=0(1)}} right. \(1)D=6^2-4cdot2cdot4=36-32=4,\y_1=frac{6+2}{2cdot4}=1, y_2=frac{6-2}{8}=0,5.\ x_1=2cdot1=2,x_2=2cdot0,5=1.\OTVEt: (2;1), (1; 0,5).$

$2)left { {{x-5y=3} atop {x^2-25y^2=15}} right. left { {{x=5y+3} atop {(5y+3)^2-25y^2=15,}} right. left { {{x=5y+3} atop {25y^2+30y+9-25y^2=15}} right. \left { {{x=5y+3} atop {30y=6}} right. left { {{x=4} atop {y=frac{1}{5} }} right.\OTVET: (4; frac{1}{5}).$

$3)left { {{x^2-y^2=21} atop {x+y=3,}} right. left { {{(x-y)(x+y)=21} atop {x+y=3}} right. left { {{3(x-y)=21} atop {x+y=3}} right.left { {{x-y=7} atop {x+y=3}} right. \left { {{x=y+7} atop {y+7+y=3,}} right. left { {{x=y+7} atop {2y=-4}} right. left { {{x=5.} atop {y=-2}} right. \OTVET: (5; -2)$

Answer 2

Вот, надеюсь помогла)