问题 解答题

计算:

(1)5s2t-2s2t;

(2)-22+20-|-3|×(-3)-1

(3)(a2b)(-2ab2)(-0.5a4b5);

(4)4m2-(-2m+3)(-2m-3).

答案

(1)原式=(5-2)s2t

=3s2t;

(2)原式=-4+1-3×(-

1
3

=-4+1+1

=-2;

(3)原式=(-2)×(-0.5)a7b8

=a7b8

(4)原式=4m2-(-2m)2+9

=9.

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