Question

repede ca rogggg Dau 15 puncte!!!!!! Si coroana​

Answer 1

Răspuns:

Explicație pas cu pas:

Inmultim ec.2 cu 2:

1a)4x +  3y = 23

-4x + 2y = 32, le adunam:

0 +5y = 55,  y =55/5 = 11

4x +3*11 = 23

4x = 23-33 = -10

x = -10/4,  x = -5/2

b) Inmultim ec.1 cu -2:

-6x -22y = -28

6x -y  = 5, le adunam:

0 +23y = -23,  y =-1

6x +1 = 5

6x = 4, x = 4/6 = 2/3

2a) y = 7-2x

x -5(7-2x) = -13

x -35 +10x = -13

11x = 22, x = 22/11 = 2

y = 7-2*2, y = 3

etc

3. a+b =67 , a> b

a = 6c + 4

6c + 4 >= [67/2] >=34

6c > 30,  c >= 5, c = 5,6,7,8,9

c = 5

a = 6*5+4, a = 34, b = 33

c=6

a = 6*6 +4, a =40, b = 27

etc

4. a+b = 20 |*-3

 3a +5b =74

etc