Question

Oblicz równania. (jeżeli ktoś by mógł to niech rozwiąże na kartce)

Answer 1

A)
- 2(5x - 2y) + 4(2x + y) = 1
3(2x - y) - (y + 7x) = 5,5

- 10x + 4y + 8x + 4y = 1
6x - 3y - y - 7x = 5,5

- 2x + 8y = 1
- x - 4y = 5,5 / * - 2

- 2x + 8y = 1
2x + 8y = - 11
dodajemy stronami
- 2x + 2x + 8y + 8y = 1 - 11
16y = - 10
y = - 10/16 = - 5/8

- 2x + 8y = 1
- 2x + 8 * - 5/8 = 1
- 2x  - 40/8 = 1
- 2x - 5 = 1
- 2x = 1 + 5 = 6
2x = - 6
x = - 6/2 = - 3
odp
x = - 3 , y = - 5/8
b)
(x + y)/2 - 2y/3 = 5/2 / * 6
3x/2 + 2y = 0 / * 2

3(x + y) - 2 * 2y = 15
3x + 4y = 0

3x + 3y - 4y = 15
3x + 4y = 0

3x - y = 15 stąd - y = 15 - 3x to y = 3x - 15
3x + 4y = 0

3x + 4(3x - 15) = 0
3x + 12x - 60 = 0
15x = 60
x = 60/15 = 4

3x + 4y = 0
3 * 4 + 4y = 0
12 + 4y = 0
4y = - 12
y = - 12/4 = - 3
odp
x = 4 , y = - 3