Question

Metoda przeciwnych wspolczynnikow:

a)3s + 5t = -6

1,5s - 2t = -3

b)5 = 3x - y

5x - 2y = 7

c)x - 3y = 5

y + 3x = -5

Answer 1

a)3s + 5t = -6 / *2

1,5s - 2t = -3 / *5

6s + 10t= -12

7,5s - 10t = -15

-1,5 s = -27 / : (-1,5)

s= 18

3*18 + 5t = - 6

54 + 5t = -6

5t = -6 - 54

5t = -50 / : 5

t = 10

b)5 = 3x - y

5x - 2y = 7

3x - y = 5 => / *(-2)

5x - 2y = 7

-6x + 2y = -10

5x - 2y = 7

-x = -3 / : (-1)

x = 3

5 * 3 - 2y = 7

15 -2y = 7

-2y = 7 -15

-2y = -8 / : (-2)

y = 4

c) x - 3y = 5

y + 3x = -5 / *3

x-3y = 5

3y + 9x = - 15

10x = -10 / : 10

x = -1

-1 - 3y = 5

- 3y = 5+1

- 2y =6 / :(-2)

y = -3