问题 计算题

化简:①2x+(x﹣4)﹣(5x﹣4)    

②3(a2﹣2a﹣3)﹣5(﹣5a2﹣2)

答案

解:①2x+(x﹣4)﹣(5x﹣4)

=2x+x﹣4﹣5x+4

=﹣2x;

②原式=3a2﹣6a﹣9+25a2+10

=28a2﹣6a+1.

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