山西中考数学复习第一单元数与式第3讲分式优选习题.docx

第3讲分式基础满分考场零失误类型一分式及其相关概念1.(2018金华)(3分)若分式x-3x+3的值为0,则x的值是(A)A.3B.-3C.3或-3D.02.(2018湖北黄冈)(3分)函数y=x+1x-1中自变量x的取值范围是(A)A.x-1且x1B.x-1C.x1D.-1x1类型二分式的运算3.(2018天津)(3分)计算2x+3x+1-2xx+1的结果为(A)A.1B.3C.3x+1D.x+3x+14.(2018河北)(3分)化简a2a-b-b2a-b的结果是(A)A.a2-b2B.a+bC.a-bD.15.(2018自贡)(3分)化简1x+1+2x2-1的结果是.6.(2018山西百校联考三)(5分)化简:x2-2x+1x3-x1-1x.7.(2018四川)(5分)化简:1-1x+1xx2-1.类型三分式的化简求值8.(2018太原一模)(5分)先化简,再求值:x-1x-x-2x+12x-1x2+2x+1,其中x=-2 018.9.(2018兰州)(5分)先化简,再求值:x-3x-4x-1x-2x-1,其中x=12.能力升级提分真功夫 10.(2018襄阳)(3分)计算:5x+3yx2-y2-2xx2-y2=.11.(2018重庆A卷)(5分)计算:x+2x-3+x+2x2-4x+4x-3.12.(2018聊城)(5分)aa+1-a-1aaa+2-1a2+2a,其中a=-12.13.(2018随州)(6分)先化简,再求值:x2x2-11x-1+1,其中x为整数且满足不等式组预测猜押把脉新中考 14.(2019原创预测)(3分)下列运算正确的是(A)A.-x-y-x+y=x-yx+yB.a2-b2(a-b)2=a-ba+bC.a2-b2(a-b)2=a+ba-bD.x-11-x2=1x+115.(2019改编预测)(5分)化简求值:1+2a-1a2+2a+1a-1,从-2a2中选一个合适的值代入求解.16.(2019原创预测)(5分)先化简,再求值:x+2x2-2x8xx-2-2+x,其中x=2-1.17.(2019原创预测)(5分)先化简,再求值:1-1a-2a2-6a+92a-4,其中a=4cos 30+3tan 45.答案精解精析基础满分1.A2.A3.C4.B5.答案1x-16.解析原式=(x-1)2x(x-1)(x+1)x-1x=(x-1)2x(x-1)(x+1)xx-1=1x+1.7.解析原式=x+1-1x+1(x+1)(x-1)x=xx+1(x+1)(x-1)x=x-1.8.解析原式=x2-1-x(x-2)x(x+1)(x+1)22x-1=2x-1x(x+1)(x+1)22x-1=x+1x,当x=-2 018时,原式=2 0172 018.9.解析x-3x-4x-1x-2x-1=x2-xx-1-3x-4x-1x-1x-2=x2-4x+4x-1x-1x-2=(x-2)2x-1x-1x-2=x-2.当x=12时,原式=12-2=-32.能力升级10.答案3x-y11.解析原式=x+2x-3+x2-x-6x-3x-3(x-2)2=x2-4x-3x-3(x-2)2=(x+2)(x-2)x-3x-3(x-2)2=x+2x-2.12.解析原式=aa+1-a-1aa2-1a(a+2)=aa+1-a-1aa(a+2)(a+1)(a-1)=aa+1-a+2a+1=-2a+1,当a=-12时,原式=-4.13.解析原式=x2x2-11+x-1x-1=x2x2-1x-1x=xx+1,解不等式组得2x3,x为整数,x=3,当x=3时,原式=33+1=34.预测猜押14.C15.解析原式=a-1+2a-1a-1(a+1)2=a+1a-1a-1(a+1)2=1a+1.由题可得a1,从-2a2中选取除1外的值均可代入求值,如取a=0,则原式=1(答案不唯一).16.解析原式=x+2x2-2x8x+(x-2)2x-2=x+2x(x-2)8x+x2-4x+4x-2=x+2x(x-2)x-2(x+2)2=1x(x+2),当x=2-1时,原式=1(2-1)(2+1)=1.17.解析原