试题与答案

计算和化简: (1)72×32÷(一3)+(-3)2; (2)-14-[2-(-

题型:解答题

题目:

计算和化简:

(1)72×32÷(一3)+(-3)2

(2)-14-[2-(-3)2];

(3)(a2-6a-7)-(a2-3a+4);

(4)-2(-3xy+2z)+3(-2xy-5x)

答案:

(1)原式=49×9×(-

1
3
)+9

=-147+9

=-138;

(2)原式=-1-(2-9)=-1-(-7)

=-1+7

=6;

(3)原式=a2-6a-7-a2+3a-4

=-3a-11;

(4)原式=6xy-4z-6xy-15x

=-4z-15x.

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