Question

Rezolvati in multimea numerelor deale sistemul de ecuatii:
$\left \{ {{3x+y=-1}\atop{x-y=5}}\right.$

Answer 1

rezulta 3x+x+y-y=5-1
4x=4
x=4/4
x=1
din x-y=5 avem 1-y=5
-y=5-1
-y=4    inmultim-1
y=-4