Notam cu "a" -> primul numar
"b"-> al doilea numar
a+b=8,7
a-b=1,3
=>Metoda I:
[tex]\left \{ {{a+b=8,7} \atop {a-b=1,3}} \right. \\-------\\2a /= 10\\a=5\\5+b=8,7\\=> b= 3,7[/tex]
Metoda 2
a+b=8,7
=> a=8,7-b
8,7-b-b=1,3
-2b=-7.4
b=3.7
a-b=1,3
a=1,3+3. 7
a=5
