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计算:(1)3x-3(2y+x)+y(2)(-2ab)(3a2-2ab-b)2(3)(−13)−1−(3.14−π)0+(−12)2(4)(a+b-3)(a+b+3)(5)(x-1)(x+3)-(x-2)2.

题目详情
计算:
(1)3x-3(2y+x)+y
(2)(-2ab)(3a2-2ab-b)2
(3)(−
1
3
)−1−(3.14−π)0+(−12)2
(4)(a+b-3)(a+b+3)
(5)(x-1)(x+3)-(x-2)2
▼优质解答
答案和解析
(1)原式=3x-6y-3x+y
=-5y;

(2)(-2ab)(3a2-2ab-b)2
=(-2ab)[(3a 2-2ab)-b]2
=-2ab•(9a4-12a3b+4a2b2+b2-6a2b+4ab2),
=-18a5b+24a4b2-8a3b3-2ab3+12a3b2-8a2b3

(3)(−
1
3
)−1−(3.14−π)0+(−12)2
=-3-1+1
=-3;

(4)(a+b-3)(a+b+3)
=[(a+b)-3][(a+b)+3]
=(a+b)2-9
=a2+2ab+b2-9;

(5)(x-1)(x+3)-(x-2)2
=x2+3x-x-3-(x2-4x+4)
=x2+2x-3-x2+4x-4
=6x-7.