Question

Va rog ajutati-ma rapid pana la 12
1.Rezolvati prin metoda substitutiei sistemele:

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

\left \{ {{-2x+4y=10} \atop {3x+2y=1}} \right.


2.Rezolvati prin metoda reducerii sistemele:

\left \{ {{x+y=7} \atop {-4x+y=-3}} \right.

\left \{ {{x+2y=3} \atop {2x+y=3}} \right.

Answer 1

Răspuns:

1. x+y=2

2x+y=-5

y=2-x

2x+y=-5

y=2-x

2x+2-x=-5

y=2-x

x+2=-5

y=2-x

x=-7

y=2-7

x=-7

y=-5

x=-7

-2x+4y=10 /:2

3x+2y=1

-x+2y=5

3x+2y=1

2y=5-x

3x+2y=1

2y=5-x

3x+5-x=1

2y=5-x

2x+5=1

2y=5-x

2x=4

2y=5-x

x=2

2y=5-2

x=2

2y=3

x=2

y=3/2

x=2

y=1.5

x=2

2. x+y=7 /4

-4x+y=-3

4x+4y=28

-4x+y=-3

5y=25

x+y= 7

y=5

x+5=7

y=5

x=2

x+2y=3

2x+y=3

2y+x=3

y+2x=3 /-2

2y+x=3

-2y-4x=-6

-3x=-3

x+2y=3

x=1

1+2y=3

x=1

2y=2

x=1

y=1