Question

qual o resultado desse sistema?

2x - y = 9
5x - 4y = 5

​

Answer 1

{2x - y = 9 ×(-4)

{5x - 4y = 5

{-8x+4y=-36

+{5x-4y=5

$- 3x = - 31 \times ( - 1) \\ 3x = 31 \\ x = \frac{31}{3}$

$2x - y = 9 \\ y = 2x - 9 \\ y = 2. \frac{31}{3} - 9 \\ x = \frac{62}{3} - 9$

$x = \frac{62 - 27}{3} \\ x = \frac{35}{3}$

Answer 2

Resposta:

2x-y= 9.(-4)

5x-4y=5

-8x+4y = -36

5x-4y= 5

corta o -4y e o +4y

-8x+ 5x= -3x

3x= -31 (-1 ) = 31

3x= 31

x= 10,3

5.10,3 -4y = 5

51,5 - 4y = 5

4y= 51,5 - 5= 46,5

4y= 46,5

y= 11,625