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化简或计算:
(1)=
(2)=
计算或化简:(1)计算:+|2?3|+sin245°(2)先化简,再求值:,其中x=-2.
计算或化简:
(1)计算:+|2?3|+sin245°
(2)先化简,再求值:,其中x=-2.
计算或化简:-=________;=________.