《福建省2019年中考數(shù)學(xué)總復(fù)習(xí) 提分專練01 數(shù)與式的運(yùn)算練習(xí)題》由會(huì)員分享,可在線閱讀,更多相關(guān)《福建省2019年中考數(shù)學(xué)總復(fù)習(xí) 提分專練01 數(shù)與式的運(yùn)算練習(xí)題(7頁珍藏版)》請?jiān)谘b配圖網(wǎng)上搜索。
1、提分專練01數(shù)與式的運(yùn)算
(17年25題,15年26題)
類型1 實(shí)數(shù)運(yùn)算
1.[2018·漳州質(zhì)檢]計(jì)算:3-1+π0-19.
2.[2018·寧德質(zhì)檢]計(jì)算:4cos30°+2-1-12.
3.[2018·涼山州]計(jì)算:∣3.14-π∣+3.14÷32+10-2cos45°+(2-1)-1+(-1)2019.
類型2 整式運(yùn)算
4.[2018·南平質(zhì)檢]先化簡,再求值:(a+2b)2-4a(b-a),其中a = 2,b = 3.
5.[2018·三明質(zhì)檢]先化簡,
2、再求值:x(x+2y)-(x+1)2+2x,其中x = 3+1,y = 3-1.
類型3 分式化簡求值
6.[2017-2018屏東中學(xué)與泉州七中聯(lián)考]先化簡,再求值:a+1-a2a-1,其中a = 2+1.
7.[2018·莆田質(zhì)檢]先化簡,再求值:aa2+2a+1÷1 - 1a+1,其中a = 3-1.
8.[2018·泉州質(zhì)檢]先化簡,再求值:(a2a-3-9a-3)÷a2+3aa3,其中a = 22.
9.[2018·龍巖質(zhì)檢]先化簡,再求值:x-3x2-1·x2+2x+1x-3-1,
3、其中x = 2+1.
10.[2018·眉山]先化簡,再求值:x-1x-x-2x+1÷2x2-xx2+2x+1,其中x滿足x2-2x-2 = 0.
參考答案
1.解:原式 = 13+1-13 = 1.
2.解:原式 = 4×32+12-23 = 12.
3.解:原式 = π-3.14+3.14÷1-2×22+12-1+(-1)
= π-3.14+3.14-2+2+1-1
= π.
4.解:原式 = a2+4ab+4b2-4ab+4a2
= 5a2+4b2,
當(dāng)a = 2,b = 3
4、時(shí),
原式 = 5×22+4×(3)2
= 20+12 = 32.
5.解:原式 = x2+2xy-(x2+2x+1)+2x
= x2+2xy-x2-2x-1+2x
= 2xy-1.
當(dāng)x = 3+1,y = 3-1時(shí),
原式 = 2(3+1)(3-1)-1
= 2×(3-1)-1
= 3.
6.解:原式 = (a+1)(a-1)a-1 - a2a-1
= a2-1a-1 - a2a-1
= a2-1-a2a-1
= -1a-1.
當(dāng)a = 2+1時(shí),原式 = -12+1-1 = -22.
7.解:原式 = a(a+1)2÷a+1-1a+1
5、 = a(a+1)2×a+1a
= 1a+1.
當(dāng)a = 3-1時(shí),
原式 = 13-1+1 = 13 = 33.
8.解:原式 = a2-9a-3÷a(a+3)a3
= (a+3)(a-3)a-3·a3a(a+3)
= a2.
當(dāng)a = 22時(shí),
原式 = 222 = 12.
9.解:原式 = x-3(x+1)(x-1)·(x+1)2x-3-1
= x+1x-1 - x-1x-1
= 2x-1.
當(dāng)x = 2+1時(shí),原式 = 22+1-1 = 22 = 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.
由題意得:x2 = 2x+2,代入得:原式 = x+12x+2 = 12.
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