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1. 计算:$2a(a^2+2b)=$ (
A.$a^3+4ab$
B.$2a^2+2ab$
C.$2a+4ab$
D.$2a^3+4ab$
D
)A.$a^3+4ab$
B.$2a^2+2ab$
C.$2a+4ab$
D.$2a^3+4ab$
答案
1.D
2.(兰州市中考)计算:$2a(a-1)-2a^2=$ (
A.$a$
B.$-a$
C.$2a$
D.$-2a$
D
)A.$a$
B.$-a$
C.$2a$
D.$-2a$
答案
2.D
3. 下列计算正确的是（
A.$(ab - 1)(-4ab^2) = 4a^2b^3 - 4ab^2$
B.$3a(a^2 + 2a + 1) = 3a^3 + 6a^2$
C.$9 - 2x(x - 3) = -2x^2 - 6x + 9$
D.$-3x(3x - 1) - 2 = -9x^2 + 3x - 2$
D
）A.$(ab - 1)(-4ab^2) = 4a^2b^3 - 4ab^2$
B.$3a(a^2 + 2a + 1) = 3a^3 + 6a^2$
C.$9 - 2x(x - 3) = -2x^2 - 6x + 9$
D.$-3x(3x - 1) - 2 = -9x^2 + 3x - 2$
答案
3.D
4.(黄石市期末)在“单项式乘多项式”的课堂上,有这样一道题的计算过程:$(x - 3y) · (-6x) = x · (-6x) □ (-3y) · (-6x)$,
“$□$”内应填的符号为 (
A.+
B.-
C.$·$
D.$÷$
“$□$”内应填的符号为 (
A
)A.+
B.-
C.$·$
D.$÷$
答案
4.A
5. 计算:
(1) $a(b+3)=$ ______;
(2) $xy^2(2x^2y - 3y)=$ ______;
(3) $(m - 6n) · (-2n)=$ ______;
(4) $\frac{1}{2}a^2b(\frac{4}{3}a^2b^2 - 2ab + 1)=$ ______
______.
(1) $a(b+3)=$ ______;
(2) $xy^2(2x^2y - 3y)=$ ______;
(3) $(m - 6n) · (-2n)=$ ______;
(4) $\frac{1}{2}a^2b(\frac{4}{3}a^2b^2 - 2ab + 1)=$ ______
______.
答案
5. (1)$ab+3a$ (2)$2x^3 y^3 - 3xy^3$ (3)$- 2mn + 12n^2$ (4)$\frac{2}{3} a^4 b^3 - a^3 b^2 + \frac{1}{2} a^2 b$
6. 计算:
(1) $(x^3 - 2x) · x^2$;
(2) $5a^2b^2(-ab + 1)$;
(3) $-2xy(3x^2 - xy + 4y^2)$;
(4) $(m^2n - \frac{1}{3}mn - 1)(-\frac{1}{4}mn^2)$.
(1) $(x^3 - 2x) · x^2$;
(2) $5a^2b^2(-ab + 1)$;
(3) $-2xy(3x^2 - xy + 4y^2)$;
(4) $(m^2n - \frac{1}{3}mn - 1)(-\frac{1}{4}mn^2)$.
答案
6. (1)解:原式$=x^5 - 2x^3$.
(2)解:原式$=-5a^3 b^3 + 5a^2 b^2$.
(3)解:原式$=-6x^3 y + 2x^2 y^2 - 8xy^3$.
(4)解:原式$=-\frac{1}{4} m^3 n^3 + \frac{1}{12} m^2 n^3 + \frac{1}{4} mn^2$.
(2)解:原式$=-5a^3 b^3 + 5a^2 b^2$.
(3)解:原式$=-6x^3 y + 2x^2 y^2 - 8xy^3$.
(4)解:原式$=-\frac{1}{4} m^3 n^3 + \frac{1}{12} m^2 n^3 + \frac{1}{4} mn^2$.
7.一个直角三角形的两条直角边分别为$4m^2$，$3m-1$，则此三角形的面积为（
A.$12m^3 -4m^2$
B.$12m^3 -4$
C.$6m^3 -2m^2$
D.$6m^3 -2$
C
）A.$12m^3 -4m^2$
B.$12m^3 -4$
C.$6m^3 -2m^2$
D.$6m^3 -2$
答案
7.C
8.若一个长方体的长、宽、高分别为$2x$，$x$，$3x - 4$，则其体积为（
A.$3x^3 - 4x^2$
B.$6x^2 - 8x$
C.$6x^3 - 8x^2$
D.$6x^3 - 8x$
C
）A.$3x^3 - 4x^2$
B.$6x^2 - 8x$
C.$6x^3 - 8x^2$
D.$6x^3 - 8x$
答案
8.C
9.如图,请计算阴影部分的面积. 
答案
9. 解:$S_{阴影} = b(2b - a) - a(2a - b) = 2b^2 - ab - 2a^2 + ab = 2b^2 - 2a^2$.
10.计算：$-2xy^2(x^2 - 2y^2 + 1) =$
.
.
答案
10.$-2x^3 y^2 + 4xy^4 - 2xy^2$
