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10. 若多项式$2x^3 -8x^2 +x -1$与多项式$3x^3 +2mx^2 -5x +3$的差不含二次项，则$m$等于(
A.2
B.-2
C.4
D.-4
D
)A.2
B.-2
C.4
D.-4
答案
10.D
二、填空题
11. 多项式$4x^2+3xy^2-xy-2$的常数项是
11. 多项式$4x^2+3xy^2-xy-2$的常数项是
-2
。答案
11.-2
12. 单项式$-\frac{5x^2y}{3}$的系数是
$-\dfrac{5}{3}$
，次数是3
.答案
12.$-\dfrac{5}{3}$，3
13. 小明手中写有一个整式$3(a+b)$，小康手中也写有一个整式，小华知道他们两人手中所写整式的和为$2(2a-b)$，那么小康手中所写的整式是________.
答案
13.$a-5b$
14. 若单项式$-2a^{1-m}b^5$与单项式$3a^2b^{n+2}$是同类项，则$m^n$的值是
-1
.答案
14.-1
三、解答题
15. 计算:
(1) $\frac{1}{3}(9x-3)-2(x+1)$;
(2) $2a-7a+3a$;
(3) $(7mn-3m^2)-2(-mn+2m^2)$;
(4) $(5a+4c+7b)+(5c-3b-6a)$;
(5) $(2a^2b-ab^2)-2(ab^2+3a^2b)$;
(6) $2x^2+1-3x-7-3x^2+5x$;
(7) $4(x^2+xy-6)-3(2x^2-xy)$;
(8) $4x^2-(2x^2+x-1)+(2-x^2-3x)$;
(9) $a^2-3ab+5-a^2-3ab-7$;
(10) $-2(-3xy+2z)+3(-2xy-5x)$;
(11) $4x^3-5xy^3-6x^2y^2-3xy^3+5x^2y^2+3$;
(12) $-a-3(a-b)+4(a-2b)$;
(13) $(2x-3y)+(5x+4y)$;
(14) $(8a-7b)-(4a-5b)$;
(15) $-3(2x-y)-2(4x+\frac{1}{2}y)+2009$;
(16) $-[2m-3(m-n+1)-2]-1$.
15. 计算:
(1) $\frac{1}{3}(9x-3)-2(x+1)$;
(2) $2a-7a+3a$;
(3) $(7mn-3m^2)-2(-mn+2m^2)$;
(4) $(5a+4c+7b)+(5c-3b-6a)$;
(5) $(2a^2b-ab^2)-2(ab^2+3a^2b)$;
(6) $2x^2+1-3x-7-3x^2+5x$;
(7) $4(x^2+xy-6)-3(2x^2-xy)$;
(8) $4x^2-(2x^2+x-1)+(2-x^2-3x)$;
(9) $a^2-3ab+5-a^2-3ab-7$;
(10) $-2(-3xy+2z)+3(-2xy-5x)$;
(11) $4x^3-5xy^3-6x^2y^2-3xy^3+5x^2y^2+3$;
(12) $-a-3(a-b)+4(a-2b)$;
(13) $(2x-3y)+(5x+4y)$;
(14) $(8a-7b)-(4a-5b)$;
(15) $-3(2x-y)-2(4x+\frac{1}{2}y)+2009$;
(16) $-[2m-3(m-n+1)-2]-1$.
答案
15. (1)$x-3$ (2)$-2a$ (3)$9mn-7m^2$ (4)$-a+4b+9c$
(5)$-4a^2b-3ab^2$ (6)$-x^2+2x-6$ (7)$-2x^2+7xy-24$
(8)$x^2-4x+3$ (9)$-6ab-2$ (10)$-15x-4z$
(11)$4x^3-8xy^3-x^2y^2+3$ (12)$-5b$ (13)$7x+y$
(14)$4a-2b$ (15)$-14x+2y+2009$ (16)$m-3n+4$
(5)$-4a^2b-3ab^2$ (6)$-x^2+2x-6$ (7)$-2x^2+7xy-24$
(8)$x^2-4x+3$ (9)$-6ab-2$ (10)$-15x-4z$
(11)$4x^3-8xy^3-x^2y^2+3$ (12)$-5b$ (13)$7x+y$
(14)$4a-2b$ (15)$-14x+2y+2009$ (16)$m-3n+4$
