помогите решить номер 6.10 под буквой а

+ 0 -

Victorvip

03 авг. 2013 г., 7:35:53 (10 лет назад)

{xy(x+y)=6
{xy+(x+y)=5
a=xy; b=x+y
{ab=6
{a+b=5  => a1=2, b1=3                    и              a2=3, b2=2
xy=2 => x=2/y                                                  xy=3 => x=3/y
x+y=3                                                               x+y=2
2/y +y=3|*y                                                       3\y+y=2|*y
y²-3y+2=0                                                         y²-2y+3=0
y1=1; y2=2                                                        D=-8<0 решений нет
x1=2/1=2; x2=2/2=1
Ответ: (2;1); (1;2)