作业帮 > 数学 > 作业

计算:(1)(-3a)3-(-a)•(-3a)2(2)4-(-2)-2-32÷(3.14-π)0(3)-0.2514×2

来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/05/14 04:53:46
计算:
(1)(-3a)3-(-a)•(-3a)2
(2)4-(-2)-2-32÷(3.14-π)0
(3)-0.2514×230
(4)1982
(5)(-2x) 2•(-0.5xy3);
(6)(3x2y-2x+1)(-2xy)
(7)(-4x-y)(4x-y)
(8)-3a(a-b)2
(9)(a+2b-3c)(a-2b-3c)
(10)(2a+b)2(2a-b)2
(1)(-3a)3-(-a)•(-3a)2
=-27a3+a×9a2
=-18a3
(2)4-(-2)-2-32÷(3.14-π)0
=4-
1
(−2) 2-9×1,
=-
21
4

(3)-0.2514×230
=-(
1
4)14×230
=-2-28×230
=-4;
(4)1982=(200-2)2
=2002-2×200×2+22
=40000-800+4,
=39204;
(5)(-2x) 2•(-0.5xy3),
=4x2•(-
1
2xy3),
=-2x3y3
(6)(3x2y-2x+1)(-2xy),
=3x2y•(-2xy)+(-2x)•(-2xy)+1•(-2xy),
=-6x3y2+4x2y-2xy;
(7)(-4x-y)(4x-y),
=(-y-4x)(-y+4x),
=(-y)2-(4x)2
=y2-16x2
(8)-3a(a-b)2
=-3a(a2-2ab+b2),
=-3a•a2-(-3a)•2ab+(-3a)•b2
=-3a3+6a2b-3ab2
(9)(a+2b-3c)(a-2b-3c),
=(a-3c+2b)(a-3c-2b),
=(a-3c)2-(2b)2
=(a2-6ac+9c2)-4b2
=a2-6ac+9c2-4b2
(10)(2a+b)2(2a-b)2
=[(2a+b)(2a-b)]2
=[(2a)2-b2]2
=(4a2-b22
=16a4-8a2b2+b4