2x-(21+5x)=x+7
=> 2x-21-5x=x+7
=> 2x-5x-x=7+21
=> -4x=28
=> x=28:(-4)
=> x=7
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2x-(21+5x)=x+7
=> 2x-21-5x=x+7
=> 2x-5x-x=7+21
=> -4x=28
=> x=28:(-4)
=> x=7