Question

Rezolvati sistemul de ecuatii: $\left \{ {{5x+3=y-5} \atop {7x-3y=7}} \right.$

Answer 1

5x - y = - 8   | * 3
7x - 3y = 7   | * (-1)
15x - 3y = - 24 si
- 7x + 3y = - 7
_______________
8x   /     = - 31
x = - 31/8
7 * (- 31/8) - 3y = 7
- 217/8 - 24y/8 = 56/8
- 24y = 217 + 56 
24y = - 273
y = 273/24
y = 91/8

Answer 2

5x - y = - 8   | * 3
7x - 3y = 7   | * (-1)
15x - 3y = - 24 si
- 7x + 3y = - 7
8x   /     = - 31
x = - 31/8
7 * (- 31/8) - 3y = 7
- 217/8 - 24y/8 = 56/8
- 24y = 217 + 56 
24y = - 273
y = 273/24
y = 91/8