система (x+y)²-5(x+y)+4=0
(x-y)²-(x-y) - 2=0​​

(х+y)

2

−5(x+y)+4=0

(x+y)=t

t

2

−5t+4=0

D=(−5)

2

−4∗4∗1=25−16=9

t

1,2

=

2

5б

9

t

1

=

2

5−3

=1

t

2

=

2

5+3

=4

x+y=1;y=1−x

x+y=4;y=4−x

(x−y)

2

−(x−y)−2=0

(x−y)=t

t

2

−t−2=0

D=(−1)

2

−4∗(−2)∗1=

9

=3

t

1,2

=

2

1б3

t

1

=

2

1+3

=2

t

1

=

2

1−3

=−1

x−y=2;x=y+2

x−y=−1;x=y−1

y=1−x;y=4−x;x=y+2;x=y−1

(x=0;y=1);(x=1,5;y=−0,5);(x=1,5;y=2,5);(x=3;y=1)