Question

2. Alege răspunsul corect!

Soluţia sistemului

-2x+3y = 10
1-4x+y=0

A. (0,1); B. (-2, 4); C. (1,4); D. (4,1).

3.Rezolva sistemele

a) 2x+4y =6
6x+3y =5

b) 8a-4b =-4
2a+5b=2

ajutooor ​

Answer 1

Răspuns:

2.

1-4x+y = 0

y = 4x -1

-2x + 3y = 10

-2x + 3(4x-1) = 10

-2x + 12x - 3 = 10

10x = 13

x = 1.3

y = 4x - 1 = 4 × 1.3 -1

y = 4.2

3.

a) 2x + 4y = 6

2x = 6 - 4y

x = 3 - 2y

6x + 3y = 5

6(3-2y) + 3y = 5

18 - 12y + 3y = 5

-9y = -13

y = 13/9

x = 3 - 2y = 3 - 2 × 13/9

x = 1/9

b) 8a - 4b = -4

4b = 8a +4

b = 2a + 1

2a + 5b = 2

2a + 5(2a + 1) = 2

2a + 10a + 5 = 2

12a = -3

a = -1/4

a = -0.25

b = 2a + 1

b = 2 × (-1/4) + 1

b = 1/2

b = 0.5