规定A△B=5A-4B.如果X△(5△2)=14,求X=_.

X△(5△2)=14,
X△(5×5-4×2)=14,
           X△17=14,
        5X-4×17=14,
           5X-68=14,
              5X=14 68,
              5X=82,
               X=16.4,
故答案为:16.4.

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