已知向量若\(\overset{\to }{{a}}\,=\left( 1,1 \right),\overset{\to }{{b}}\,=\left( 2,x \right)\),若\(\overrightarrow{a}+\overrightarrow{b}\)与\(\overrightarrow{a}-\overrightarrow{b}\)平行,则实数\(x\)的值是( )
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