\(\left(A+9\right)+\left(A-8\right)+\left(A+7\right)+\left(A-6\right)+\left(A+5\right)+\left(A-4\right)=63.3\)
\(\Leftrightarrow\left(A+A+A+A+A+A\right)+\left(9-8+7-6+5-4\right)=189\)
\(\Leftrightarrow6A+3=189\)
\(\Leftrightarrow6A=186\)
\(\Leftrightarrow A=31\)
Vậy A = 31
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