2019年中考數(shù)學(xué)總復(fù)習(xí) 提分專練01 實數(shù)的運算與代數(shù)式的化簡求值練習(xí) 湘教版.doc

提分專練 (一)實數(shù)的運算與代數(shù)式的化簡求值|類型1|實數(shù)的混合運算1.xx通遼計算:-|4-12|-(-3.14)0+(1-cos30)12-2.2.xx青海計算:3tan30+38+-12-1+(-1)xx.|類型2|整式的化簡求值3.xx邵陽先化簡,再求值:(a-2b)(a+2b)-(a-2b)2+8b2,其中a=-2,b=12.4.已知4x=3y,求代數(shù)式(x-2y)2-(x-y)(x+y)-2y2的值.|類型3|分式的化簡求值5.xx婁底先化簡,再求值:1x+1+1x2-1xx2+2x+1,其中x=2.6.xx撫順先化簡,再求值:1-x+3x+1x2+4x+4x+1,其中x=tan45+12-1.參考答案1.解:原式=-(4-12)-1+(1-cos30)4=-4+23-1+4-4cos30=23-1-432=-1.2.解:原式=333+2+(-2)+1=1+2-2+1=2.3.解:原式=a2-4b2-(a2-4ab+4b2)+8b2=a2-4b2-a2+4ab-4b2+8b2=4ab.當a=-2,b=12時,原式=4ab=4(-2)12=-4.4.解:(x-2y)2-(x-y)(x+y)-2y2=x2-4xy+4y2-(x2-y2)-2y2=-4xy+3y2=-y(4x-3y).4x=3y,原式=0.5.解:原式=x-1+1(x+1)(x-1)(x+1)2x=x+1x-1.當x=2時,原式=2+12-1=(2+1)2=22+3.6.解:原式=1-x2+3x+1(x+2)2x+1=(2+x)(2-x)x+1x+1(x+2)2=2-xx+2,x=tan45+12-1=1+2=3,原式=-15.