初一数学代数式求值4道题目，求大神帮我！（要有过程） 初一数学。有过程的要过程。填空题。（求大神帮忙）
\u6c42\u5927\u795e\u5e2e\u6211\u89e3\u4e0b\u8fd9\u56db\u9053\u6781\u9650\u6570\u5b66\u9898\uff0c\u8981\u6709\u8fc7\u7a0b\uff0c\u8c22\u8c22\u4e86\uff01\u5e94\u7528\u65e0\u7a77\u8fd1\u4f3c\u503cx\u8d8b\u4e8e0\u65f6limx/sinx=1\uff0climx/ln\uff08x+1\uff09=1
=limx²/sin²x\uff082+\u221a\uff084-x²\uff09\uff09=lim1/\uff082+\u221a\uff084-x²\uff09\uff09=1/4
=lim\uff08x-2x\uff09/3x=-1/3
=lim\uff081-1/n\uff09²/\uff081+1/n²\uff09=\uff081-0\uff09²/\uff081+0\uff09=1
=lim\uff082+1/x-5/x²\uff09/\uff081-2/x+1/x²\uff09=\uff082+0-0\uff09/\uff081-0+0\uff09=2
11)
3x-9=1/3x-1
8/3x=8
x=3
12)
1-2+x=1-x
x-1=1-x
x=1
2x^2-7=2-7=-5
13)
x+x+7+x+14=63
3x+21=63
x=14
\u6240\u4ee5\u5206\u522b\u662f14,21,28
14)
\u4e24\u8fb9\u540c\u65f6\u4e58\u4ee510:
2x-4=20-(5x+15)
7x=9
x=9/7
3x-2=b=27/7 - 2=13/7
\u6240\u4ee5b=13/7
15)
2x=4/3
x=2/3
3(x+a)=a-5x \u628ax=2/3\u4ee3\u5165
2+3a=a-10/3
16/3=-2a
a=-8/3
a-1=-11/3
16)
m+3=2m-2
m=5
2n=n+1
n=1
2,=-2a²b²-4ab=3又1\2
3，=x+y-z-2x+y-3x+3y-3z=-4x+5y-6z=13.5
绛旓細1,=(1+5)m²-3m²+4m+5m+2=2m²+9m+2=17\4 2,=-2a²b²-4ab=3鍙1\2 3锛=x+y-z-2x+y-3x+3y-3z=-4x+5y-6z=13.5
绛旓細15銆(x+5)(x+6)=x^2+11x+30 16銆(2x+1)(2x+3)=4x^2+6x+2x+4=4x^2+8x+4 17銆3x^3y脳(2x^2y-3xy)=6x^5y^2-9x4y^2 18銆2x脳(3x^2-xy+y^2)=6x^3-2x^2y+2xy^2 19銆(a^3)^3梅(a^4)^2=a^9/a^8=a 20銆(x^2y)^5梅(x^2y)^3 =x^2y)^2 ...
绛旓細4.浠=2鍒嗕箣a=3鍒嗕箣b=4鍒嗕箣c 鍒檃=2x,b=3x,c=4x 鎵浠3a-b+c鍒嗕箣a+2b-c =6x-3x+4x鍒嗕箣2x+6x-4x =7x鍒嗕箣4x =7鍒嗕箣4
绛旓細A 4 B 6 C 8 D10 鑻+b+c=0锛屽垯a(1/b+1/c)+b(1/a+1/c)+c(1/b+1/a)鐨勫间负___璁緈鐨2娆℃柟+m-1锛0锛屽垯m鐨3娆℃柟+2涔樹互m鐨2娆℃柟+1997锛漘__宸茬煡a-b=1,c-a=2,鍒欙紙a-b)鐨3娆℃柟+(c-d)鐨3娆℃柟+锛坈锛峚锛夛紳___宸茬煡a涔樹互b鐨2娆℃柟锛6锛屾眰ab(a涔樹互b鐨3娆℃柟+a鐨...
绛旓細鍥銆佸埄鐢ㄦ暣浣撴濇兂 渚4銆宸茬煡浠ｆ暟寮弜2+4x锛2鐨勫间负3,姹備唬鏁板紡2x2+8x锛5鐨勫兼槸澶氬皯?鍒嗘瀽銆鐢变簬x2+4x锛2鐨勫间负3,鍗硏2+4x锛2锛3,鍙互瀵瑰緟姹傚鐨勪唬鏁板紡缁忚繃閫傚綋鍦板彉褰,閫氳繃鏁翠綋浠ｅ叆姹傝В.瑙ｃ鍥犱负x2+4x锛2鐨勫间负3,鍗硏2+4x锛2锛3,鎵浠2+4x锛5,鎵浠ュ綋x2+4x锛5鏃,2x2+8x锛5锛2(x2...
绛旓細1/x-1/y=3 閫氬垎 (y-x)/xy=3 y-x=3xy x-y=-3xy 鍘熷紡=[2(x-y)-14xy]/[(x-y)-2xy]=[2(-3xy)-14xy]/[(-3xy)-2xy]=-20xy/(-5xy)=4
绛旓細浠ｆ暟寮弜+4=( )5銆佷唬鏁板紡x²+2008鐨勬渶灏忓兼槸( )锛屾鏃秞=( )6銆佸凡鐭ワ細a²+3a+5=7锛屾眰3a2+9a-2鐨勫 7銆佸凡鐭3a²-a-2=0锛屽垯5+2a-6a2=( )8銆佸凡鐭ワ細a,b浜掍负鐩稿弽鏁帮紝c,d浜掍负鍊掓暟锛宮=2锛屾眰浠ｆ暟寮鐨勫 9銆佸綋a=-1,b=-6鏃讹紝浠ｆ暟寮廰(b+ab)鐨勫兼槸锛 锛
绛旓細鎵浠^2+x=1 2x^2+2x-b=2(x^2+x)-b=2-b 2)x^2*(2x)^3-x(3x+8x^4)=8x^5-3x^2-8x^5 =3x^2 =3*2^2 =12 3)4a^2-5a+2-6a^2+6a-3 =-2a^2+a-1 =-2(-1/2)^2-1/2-1 =-1/2-1/2-1 =-2 4)3x^2+2x-5x^2-x+1 =-2x^2+x+1 =-2*(-1)^2-...
绛旓細ab=2(a+b),bc=3(b+c),ca=4(c+a),(a+b)/(ab)=1/2,(b+c)/(bc)=1/3,(c+a)/(ca)=1/4 1/a+1/b=1/2 1/b+1/c=1/3 1/c+1/a=1/4 3寮忕浉鍔犲緱:1/a+1/b+1/c=13/24 1/a=5/24,a=24/5 1/b=7/24,b=24/7 1/c=1/24,c=24 锛坅-1锛夛紙b-1锛夛紙c...
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