Ответы и объяснения

2013-05-28T02:26:24+00:00

\left \{ {y-x=-5} \atop {x^{2}-2xy-y^{2}=17}} \right;

\left \{ {{y=5+x} \atop {x^{2}-2x(-5+x)-(-5+x)^{2}}} \right.

x^{2}-2x(-5+x)-(-5+x)^{2}-17=0

x^{2}+10x-2x^{2}-(25+(-10x)+x^{2})-17=0

x^{2}+10x-2x^{2}-25+10x-x^{2}-17=0

-2x^2+20x-42=0   /-2

x^2-10x+21=0

x1+x2=10

x1*x2=21

x1=3

x2=7

y1=-5+x1=-5+3=-2

y2=-5+x2=-5+7=2