Răspuns :
a+b=27,8
a-b=1,2⇒a=1,2+b
1,2+b+b=27,8
2b=26,8
c=26,6 :2
b=13,3
b=27,8-13,3
b=14,5
a-b=1,2⇒a=1,2+b
1,2+b+b=27,8
2b=26,8
c=26,6 :2
b=13,3
b=27,8-13,3
b=14,5
[tex] \left \{ {{a+b=27,8} \atop {a-b=1,2}} \right.\\
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2a=29=\ \textgreater \ a=14,5\\
14,5+b=27,8=\ \textgreater \ b=27,8-14,5=\ \textgreater \ b=13,3\\\\
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13,3+14,5=27,8(corect)\\
14,5-13,3=1,2(corect)[/tex]