Question

请给几道多项式与多项式相乘的计算题!

Answer 1

一、填空题
1．(a+b)(m+n)
=______.
2．二项式与三项式相乘，在未合并同类项之前，积的项数为________.
3．(x+2)(x–1)
=__________;
(a–3)(a–4)
=________.
4．(x+a)(x+b)
=________.
5．(2x–3)(2x+1)
=________.
6．(3m–n)(3m+n–1)
=________.
7．(x+____
)(x–____)
=
x2
–7x
–18;
(____+2)(3xy–____)
=9x2y2
–9xy
–10.
8．(a+b)(a2
–ab+b2)
=________.
9．(x
–y)
2
=
(x
–y)(x
–y)
=________.
10．应用第9题，计算(x
–y)
3
=________.
二、判断正误(正确的划“√”，错误的划“╳”)
1．(x+1)(x
–2)
=
x2
–3x
–2.
(
)
2．(a
–b)(m–n)
=
am
+an
–bm
–bn.
(
)
3．(a
–b)
2
=
a2
–2ab+b2.
(
)
4．(2a
–1)(1+2a)
=
4a2
+4a
–1.
(
)
5．(x
–4)(y
–3)
=x2
–7x+12.
(
)
6．(3x
–2y)(3x+4y)
=
9x2
+2xy
–8y.
(
)
三、选择题（请将正确答案前的字母填入括号内）
1．(x+5)(x
–7)的计算结果是（
）.
(A)
x2
–12x
–35
(B)
x2+12x
–35
(C)
x2
–2x
–35
(D)
x2
+2x
–35
2．下列各式中，结果错误的是（
）.
(A)
(x+2)(x
–3)
=x2
–x
–6
(B)
(x
–4)(x+4)
=
x2–
16
(C)
(2x
+3)(2x
–6)
=
2x2
–3x
–18
(D)
(2x
–1)(2x+2)
=4x2
+2x
–2
3．(3x+5a)(a
–3x)的计算结果是
(
).
(A)
9x2
+12ax
–5a2
(B)
9x2
–12ax
–5a2
(C)
9x2
–12ax
+5a2
(D)
–9x2
–12ax
+5a2
4．(x
–a)(x2+ax
+a2)
的计算结果是
(
).
(A)
x3
+2ax2
–a3
(B)
x3
–a3
(C)
x3
+2a2x
–a3
(D)
x2
+2ax2
+2a2
–a3
5．下列各式中，正确的是（
）.
(A)
(2xy
–1)(xy
–3)
=2x2y2
–4xy
+3
(B)
(2m
–n)(n+2m)
=
4m2
–2mn
–n2
(C)
(y
–1)(y+1)
(2y2+1)
=2y4
–3y2
–1
(D)
(x
–3)(x
–1)
(x+1)
=x3–3x2–x+3
6．三个连续奇数，最小的一个为n，则它们的积为（
）.
(A)
n3
+6n2
+8n
(B)
n3
+3n2
+2n
(C)
n3+8n3
+6n
(D)
n3
–4n
四、计算题
1．(x+2)(x+2)
2．(x2
+3x
–1)(x
+1)
–
(x2
–2)(x
–4)
3．(3x3
–8x2
–2x
+20)(x2
+x
–1)
五、解方程
(x
–1)(x+1)
=
(x
+2)(x
–2)
+x
参考答案
一、1．am
+an
+bm
+bn；
2.6；
3．x2
+x
–2,
a2
–7a
+12；
4．x2
+(a
+b)
x
+ab；
5．4x2
–4x
–3；
6．9m2
–3m
–n2
+n；
7．2,
9;
3xy,
5;
8.a3
+b3;
9.
x2
–2xy
+y2
10．x3
–3x2y
+3xy2
–y3;
二、1.
╳；2.
╳；3.
√；4.
╳；5.
╳；6.
╳.
三、1.
(C)；2.
(C)；3.
(D)；4.
(B)；5.
(D)；6.
(A).
四、1.
x2
+4x
+4；
2.
8x2
+4x
–9;
3.
3x5
–5x4
–13x3
+26x2
+22x
–20.
五、1．x
=3.