问题 解答题

先化简,再求值.

(1)当a=1.3时,求5a+8a-8的值.

(2)当x=5时,求16x×2+23的值.

答案

(1)当a=1.3时,

5a+8a-8,

=13a-8,

=13×1.3-8,

=16.9-8,

=8.9;

(2)当x=5时,

16x×2+23,

=32x+23,

=32×5+23,

=160+23,

=183.

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