初中数学整式加减与非负性综合习题含答案

1、整式加减与非负性综合习J一.选择题(共5小题)1.若 la-21+ (+3) 2=0,则式子(+5。)- (3-2a) - 1 的值为()A.- 11B.- 1C.11D.12.若Lx - 21+ (x - y - 1) 2=0,则多项式-y - (AT+2y2)的值为()A.-7B.5C-5D.- 133.若(a+1) 2+l/?-2l=0,化简”(?y+2) - b Cx2y-xy2)的结果为()A.3x2yB.- 3xy+xy2C.- 3x1y3xy2D.3x2y - xy24 .若 k+3l+ (厂工)2=o,则整式 4x+ (3x-5y) -2的值为()«2A. -22B.

2、 -20C. 20D. 225 .已知(a-1) 2+l2t/+x+3l=0,且 a+V0,则la+3 - 13 - a-I的结果是()A. 2B. -2C. 0D.-8二.填空题（共10小题）6 .己知(。+2) 2+3-11=0,则 6。-勿活-3 (ab- 1) =.7 .若(+1) 2+协-21=0,化简”(x22) - b (fy-2)的结果为8 .已知h-2l+l+ll=0,贝lj (a+b) - (b-a) =.9 .已知(a - 2) 2+1/?+11=0,则代数式加2b - 3曲2 -(小-4a田)=10 .已知(a+1) 2+协-21=0,则 2 (。2-1力-(3cr+h

3、)的值等于.11 .若la-31+ (2b-4) 2=0,则 3 (a-b) -2 (2a - 3b)的值是.12 .若L+1I+ (-)2=0,则5/+3庐+2 (/_庐)-的值等于213 .已知(x-1) 2+41)-61=0,则 5x+6v - 4x - 8v=,14 .若A-1I+ (y+3) 2=0,则 5/- (A - 3y) =.15 .若(3皿-5) 2+ln+3l=0.贝lj 6， - (n+2) =.三,解答题(共5小题)已知u16 .先化简，再求值： 2=0，求代数式4ab- 3ab-2 (4ab+yab)-5ab 与勺值.17 .若 G+2) 2+ly- 11=0.求

4、4»-2 (2?+5xy-y2) +2 (x2+3xy)的值.18 .已知(x+2) 2+ly-l|=0,求2A2y)-4-2A的值.19 .先化简,再求值：2 (30,-2加)-3 (-加+37万)，其中L- I% (h+2) 2=0.20 .若以+61+ (3-y) 2=0 .化简并求多项式4-3 (x-2y)- (2y-3x)的值.第1页（共1页）整式加减与非负性综合习题参考答案与试题解析选择题(共5小题)1 .解：原式=a+5 - 3h+2ci - 1 =3a+2Z? - 1,VL/-2I+ (H3) 2=0,b- - 3,则原式=6 - 6 - 1= - 1, 故选：B.2

5、 .解：VLv-2l+ (x-y - 1) 2=0,，x=2, y= 1 则原式=-1 - 6= - 7, 故选:A.3 .解：V (a+1) 2+b - 21=0,/ u+ =0, b - 2=0,即 u 1, b=2,则原式=-(fy+xy?) - 2(A'2y - xy2) = - x2y - xy2 - ?jry+2xy2= 3jry+xy2. 故选：B.4 .解：VIa+3I+ (v-)2=0, . 2 , 1.x= - 3, y=. 2则原式=4x+3x - 5y - 14x+3y= - 7x - 2y=21 - 1=20, 故选：c.5 .解: (a-1) 2+I2<

6、;/+x+3I=0> ci - 1 =0,且 2a+x+3=0,解得：a=l, a= - 5,/+b<0,a+h+x=a+b - 5 V0, 3 - a - b 3 - (a+b) >0,贝llo+xl - 13 - - h= - a - % - x - 3+a+h= - x - 3=5 - 3=2.故选：A.二.填空题（共10小题）6 .解：:(4+2) 2+128-11=0,，。+2=0, 2/?- 1=0,即 =-2, =2，2则原式=6a/? - 2ab - 3t/?+3=ab+3 - 1+3=2.故答案为：27 .解：7 (d+1) 2+1-21=0,-1, b=2

7、,a (jTy+xy1) - b - x/)=-x2y - xy2 - Zry+Zvy2=-3x2y>+xy2.故答案为：-3fy+xy2.8 .解：由h21+心+11=0可得la-21=0, l+ll=0,所以 a - 2=0, +1=0,解得 ” =2, b= - 1,所以(“+5) - (-a) =24=4,故答案为4.9 .解：当 ”=2, b= - 1 时，原式=2, -3ub2 - a2b+4ab2=a2l7+ab2=4X ( - 1) +2X1=-4+2=-2故答案为：-210 .解：V(6/+1) 2+h - 21=0./ </+1 = 0, b - 2=01解得，

8、a= - 1, =2,：.2 (a2-b) - (3a2+b)= 2a2 - 2b - 3a2 - b=_ ,J _ 3b=-(-1) 2-3X2=-1 - 6=-7,故答案为：-7.11 .解：Vk/ - 31+ (2-4) 2=0,4=3, /)=2,A3 (</-/?) -2 (2a-3b)=3a - 36 - 4a+6b=-a+3b=-3+6=3.故答案为：3.12,解:原式=5/+3庐+2a2 2廿-5/+3庐=2/+4b-VL/+1I+ (-工)2=0,2，a+l=0, /? - -=0t 即 a=-l, b=,22则原式=2+1 = 3.故答案为：313 .解：V (x -

9、 1) 2+4ly - 61=0,，x-l=0, y - 6=0,即 x=l, y=6,则原式=x - 2y= 1 - 12= - 11.故答案为：-11.14 .解：Vlx- 11+ (y+3) 2=0,Ax=L y= - 3,，5，- (x-3y) =5- (1+9) =5 - 10= - 5,故答案为-5.15 .解：由题意可知：3？-5=0, +3=0,31=5, = - 3,，原式=6l +2= 2X5- ( -3) +2第1页（共1页）= 10+3+2= 15,故答案为：15三.解答题(共5小题)16 .解：4ab- 3ab-2 (4ab+yab)-5ab=4ab - (3ab -

10、 Sab2 - ab) - 5ab2=4ab - 3ab+Sab2+ab - 5ub2=3a序+2ab.又(2) 2>0, 23；.a - i=0> (+2) 2=0.23.a=-9 b="-.23当 a=-9 h= - ZfH4, 23原式= 3XX ( -2) 2+2X-1x ( -2) 2323_2 2 I 一 , 3 3=0.17 .解：V (x+2) 2+ly- ll=0>/.x= - 2, y=l,原式=4xy - 4x2 - 10xy+2v2+2.¥2+6Ay=2y-21= 2-8=-618 .解：/ (x+2) 2+|y-l|=0, -2Ax= - 2, y=, . 2则原式=57y -2x2y+4 - 2xy=x2y - xy2+4=2-hin-4=«219 .解：原式=64 -