（全国）2019版中考数学复习提分专练（一）实数混合运算与代数式的化简求值试题.docx

提分专练(一)实数混合运算与代数式的化简求值|类型1|实数的混合运算1.2018成都 计算:2-2+38-2sin60+|-3|.2.2018南充 计算:(1-2)2-1-220+sin45+12-1.3.2017长沙改编 计算:|-3|+(-2019)0-2sin30+13-1.4.2018德阳 计算:(-3)2+12-3-(32)0-4cos30+63.|类型2|整式的化简求值5.2018无锡 计算:(x+1)2-(x2-x).6.2018江西 计算:(a+1)(a-1)-(a-2)2.7.2018衡阳 先化简,再求值:(x+2)(x-2)+x(1-x),其中x=-1.|类型3|分式的化简求值8.2018聊城 先化简,再求值:aa+1-a-1aaa+2-1a2+2a,其中a=-12.9.2018株洲 先化简,再求值:x2+2x+1y1-1x+1-x2y,其中x=2,y=2.10.2018眉山 先化简,再求值:x-1x-x-2x+12x2-xx2+2x+1,其中x满足x2-2x-2=0.11.2018达州 化简代数式:3xx-1-xx+1xx2-1,再从不等式组x-2(x-1)1,6x+103x+1的解集中取一个合适的整数值代入,求出代数式的值.|类型4|与二次根式有关的计算12.2017湖州 计算:2(1-2)+8.13.2018陕西 计算:(-3)(-6)+|2-1|+(5-2)0.14.2018恩施州 先化简,再求值:1x2+2x+11+3x-1x+2x2-1,其中x=25-1.15.2017凉山州 先化简,再求值:1-a2+4ab+4b2a2-aba+2ba-b,其中a,b满足(a-2)2+b+1=0.参考答案1.解:2-2+38-2sin60+|-3|=14+2-232+3=94.2.解:原式=2-1-1+22+2=322.3.解:原式=3+1-1+3=6.4.解:原式=3+8-1-432+23=3+8-1-23+23=10.5.解:(x+1)2-(x2-x)=x2+2x+1-x2+x=3x+1.6.解:原式=a2-12-(a-2)2=a2-1-(a2-4a+4)=a2-1-a2+4a-4=4a-5.7.解:原式=x2-4+x-x2=x-4.当x=-1时,原式=-1-4=-5.8.解:aa+1-a-1aaa+2-1a2+2a=aa+1-a-1aaa+2-1a(a+2)=aa+1-a-1aa2a(a+2)-1a(a+2)=aa+1-a-1aa2-1a(a+2)=aa+1-a-1aa(a+2)a2-1=aa+1-a-1aa(a+2)(a+1)(a-1)=aa+1-a+2a+1=a-(a+2)a+1=a-a-2a+1=-2a+1,当a=-12时,原式=-2-12+1=-212=-212=-22=-4.9.解:x2+2x+1y1-1x+1-x2y=(x+1)2yx+1-1x+1-x2y=(x+1)2yxx+1-x2y=x(x+1)y-x2y=x2+xy-x2y=x2+x-x2y=xy.当x=2,y=2时,原式=2.10.解:原式=(x-1)(x+1)-x(x-2)x(x+1)(x+1)2x(2x-1)=2x-1x(x+1)(x+1)2x(2x-1)=x+1x2.由题意得:x2=2x+2,代入得:原式=x+12x+2=12.11.解:解不等式,得x1,解不等式,得x-3,不等式组的解集为-3x1.3xx-1-xx+1xx2-1=3x(x+1)-x(x-1)(x-1)(x+1)x2-1x=3x(x+1)-x(x-1)(x-1)(x+1)(x-1)(x+1)x=3(x+1)-(x-1)=3x+3-x+1=2x+4.x0,x1,当x取-2时,原式=2(-2)+4=0.12.解:原式=2-22+22=2.13.解:(-3)(-6)+|2-1|+(5-2)0=18+2-1+1=32+2=42.14.解:1x2+2x+11+3x-1x+2x2-1=1(x+1)2x+2x-1(x+1)(x-1)x+2=1x+1.当x=25-1时,原式=125-1+1=510.15.解:1-a2+4ab+4b2a2-aba+2ba-b=1-(a+2b)2a(a-b)