Explicație pas cu pas:
[tex]x + y = 1 \\ x - y = 4 \\ \\ 2x = 1 + 4 \\ 2x = 5 \\ x = \frac{5}{2}\\ \\ \frac{5}{2} + y = 1 \\ y = 1 - \frac{5}{2} = \frac{2 - 5}{2} \\ y = - \frac{3}{2} [/tex]
