问题 解答题

已知a=5,b=0.4,c=21式子3a-6b+2c的值是______.

答案

3a-6b+2c,

=3×5-6×0.4+2×21,

=15-2.4+42,

=12.6+42,

=54.6;

故答案为:54.6.

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