Question

5(x+3y)-(7x+8y)=-6 7x-9y-2(x-18y)=0 metodo de sustitución

Answer 1

5(x + 3y) - (7x + 8y) = - 6

5x + 15y - 7x - 8y = - 6

5x - 7x + 15y - 8y = - 6

1) - 2x + 7y = - 6

7x - 9y - 2 (x - 18y) = 0

7x - 9y - 2x + 36y = 0

7x - 2x - 9y + 36y = 0

2) 5x + 27y = 0

1) - 2x + 7y = - 6 (5)

2) 5x + 27y = 0 (2)

- 10x + 35y = - 30

10x + 54y = 0

----------------------------

0x + 89y = - 30

89y = - 30

y = - 30/89

El valor de y lo reemplazo en ecuación 1

- 2x + 7y = - 6

- 2x + 7 (- 30/89) = - 6

- 2x - 210/89 = - 6

- 2x = - 6 + 210/89

- 2x = (- 6 * 89 + 210)/89

- 2x = (- 534 + 210)/89

-2x = - 324/89

x = - 324/89/-2/1

x = - 324/-178

x = 162/89

Solución :

x = 162/89

y = y = - 30/89