数学初一计算题,求学霸,要过程,急急急求,拜托啊啊 数学共三小题计算题,求学霸,初一的,急急急,拜托写出过程,高...
\u6570\u5b66\u521d\u4e00\u8ba1\u7b97\u9898\uff0c\u6c42\u5b66\u9738\uff0c\u62dc\u6258\u4e86\uff0c\u6025\u6025\u6025\uff0c\u62dc\u6258\u554a\u554a\u554a\u554a\uff0c\u6c42\uff0c\u9ad8\u60ac\u8d4f\uff0c\u5171\u4e09\u5c0f\u9898第一题 -9/8÷10/9
=-9/8×9/10
=-81/80
第二题 =-27/8÷(-9/4)
=-27/8×(-4/9)
=3/2
1:-80分之81
2:2分之3
先化成分数,除号化乘号,其后分数上下颠倒
绛旓細鍥炵瓟锛氱涓棰 -9/8梅10/9 =-9/8脳9/10 =-81/80 绗簩棰 =-27/8梅(-9/4) =-27/8脳(-4/9) =3/2
绛旓細鍥炵瓟锛氫竴寮忎箻3寰楀埌 3:3x-3y=9 3寮忓噺2寮忓緱鍒 4: 5y=-5 鍗 y=-1 灏嗗畠浠e叆1寮,瑙e緱x=2
绛旓細19(1)=2 + 1 + 6 + 6=15 (2)瑙o細涓よ竟鍚屼箻4 2(2x-1) - (2x+3)=4 4x - 2 - 2x - 3=4 2x=9 x=9/2 21銆佸師寮=2a² - 5a - 2a² - 6a + 10 =-11a + 10 =-11•(-3/11) + 10 =3+10 =13 ...
绛旓細瑙:瑙佷笅鍥
绛旓細瑙o細=(-1/10)+8(1/3)-11(2/3)+1/10 =8(1/3)-11(2/3)=25/3-35/3 =-3(1/3)瑙o細=(-8/12)-1/12+3/12 =-6/12 =-1/2 瑙o細=(-1/3)-(3/4)-(5/6)=(-4/12)-(9/12)-(10/12)=-23/12 =-1(11/12)...
绛旓細(1)鍘熷紡=[(2x+y)+1]*[(2x+y)-1]=(2x+y)²-1²=(2x+y)²-1 =4x²+4xy+y²-1 (2)鍘熷紡=[(ab+1)+(ab-1)]*[(ab+1)-(ab-1)]=2ab*2 =4ab
绛旓細(1) 鍘熷紡=-49+2脳9-6梅1/9 =-49+18-54 =-31-54 =-85 (2) 鍘熷紡=-1-{-27+銆3-0.4脳3/2銆懨2} =-1+27-[3-0.6]梅2 =26-2.4梅2 =26-1.2 =24.8
绛旓細锛1锛塠4a²b²(3b²-5ab)锛峚²(-2b)³]梅8a²b³=(12a²b^4-20a³b³-8a²b³)梅8a²b³=3/2b-5/2a-1 锛2锛(5脳10^5)•锛-6脳10^-2锛壝凤紙-1/2脳10^-2锛=500000路-0.06梅-0.005 =...
绛旓細鍘熷紡=[x³-2x²+3x-3x]梅1/2x²=锛坸³-2x²锛壝1/2x²=x³梅1/2x²-2x²梅1/2x²=2x-4 鍘熷紡=6a²b³梅4a²b²脳锛4a²b-3a+1锛=3/2 b脳锛4a²b-3a+1锛=6a²b²-9/2ab...
绛旓細鍥炵瓟锛2^2-5脳1/5+|-2| =4-1+2=5 2脳(-5)+2^3-3梅1/2 =-10+8-6=-8