Решите систему уравнений {x-y=7 {x*y=-10

X = Y + 7 Y*( Y + 7) = - 10 Y^2 + 7Y + 10 = 0D = 49 - 40 = 9√ D = 3 Y1 = ( - 7 + 3 ) : 2 = - 2 Y2 = ( - 10) : 2 = - 5 X = Y + 7 X1 = - 2 + 7 = 5 X2 = - 5 + 7 = 2 Ответ ( 5 ; - 2 ) ; ( 2 ; - 5 ) 

[latex] left { {{x-y=7} atop {x*y=-10}} ight. \ x=7+y \ y(7+y)=-10 \ y^{2} +7y+10=0 \ D=49-40=9 \ sqrt{D} =3 \ y _{1} = frac{-7+3}{2} = frac{-4}{2} =-2 \ y _{2} = frac{-7-3}{2} = frac{-10}{2} =-5 \ x_{1} =7-2=5 \ x_{2} =7-5=2 \ left { {{x=5} atop {y=-2}} ight. left { {{x=2} atop {y=-5}} ight. [/latex]