Question

Exercitide de mai jos va rog urgemnt ! DAu coroana ! NU raspundeti daca nu stiti

Answer 1

1)

{2x+y=-2 |•3

{x+3y=-1

{6x+3y=-6

{x+3y=-1

___________

"-"

6x-x+3y-3y=-6-(-1)

5x=-5|:5

x=-1

x+3y=-1

3y=-1-x

3y=-1-(-1)

3y=-1+1

3y=0

y=0

2)

{x+2y=1|•3

{3x+y=8

{3x+6y=3

{3x+y=8

__________

"-"

5

5y=-5|:5

y=-1

3x+y=8

3x=8-y

3x=8-(-1)

3x=8+1

3x=9

x=9/3

x=3

7)

{x-y=2→x=2+y

{2x+y=7→2(2+y)+y=7

4+2y+y=7

3y=7-4

3y=3|:3

y=1

x=2+y→x=2+1

→x=3