Решить систему уравнений: 10*(x+4)*(y+1) = 30*(x-1)*(y-1) - вопрос №6942004104130113011 от sanymoskva 07.12.2020 15:58

Question

Алгебра: Решить систему уравнений: 10*(x+4)*(y+1) = 30*(x-1)*(y-1) , 30*(x-1)*(y-1) = 20*x*y

sanymoskva · Answer

{10(x+4)(y+1)=30(x-1)(y-1){30(x-1)(y-1)=20xy10(x+4)(y+1)=20xy(x+4)(y+1)=2xyxy+x+4y+4=2xyxy-x=4y+4x(y-1)=(4y+4)x=(4y+4)/(y-1)10[(4y+4)/(y-1)+4](y+1)=30[(4y+4)/(y-1) -1](y-1)[(4y+4)/(y-1)+4](y+1)=3[(4y+4)/(y-1) -1](y-1)(4y+4+4y-4)(y+1)/(y-1)=3(4y+4-y+1)(y-1)/(y-1)8y(y+1)=(9y+15)(y-1),y≠18y²+8y=9y²-9y+15y-15y²-2y-15=0y1+y2=2 U y1*y2=-15y1=-3⇒x1=(-12+4)/(-3-1)=-8/(-4)=2y2=5⇒x2=(20+4)/(5-1)=24/4=6ответ (2;-3);(6;5)...