数学题,快写清过程,谢谢1.已知(a-2b)/b=5/3求(a+b)/b的值2.设x=a/(b+c)=b/(a+c)=c/(b+a),求x的值3.已知p是直线AB上一点AP:PB=3:5,求AB:PB的值
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![数学题,快写清过程,谢谢1.已知(a-2b)/b=5/3求(a+b)/b的值2.设x=a/(b+c)=b/(a+c)=c/(b+a),求x的值3.已知p是直线AB上一点AP:PB=3:5,求AB:PB的值](/uploads/image/z/2655539-35-9.jpg?t=%E6%95%B0%E5%AD%A6%E9%A2%98%2C%E5%BF%AB%E5%86%99%E6%B8%85%E8%BF%87%E7%A8%8B%2C%E8%B0%A2%E8%B0%A21.%E5%B7%B2%E7%9F%A5%28a-2b%29%2Fb%3D5%2F3%E6%B1%82%28a%2Bb%29%2Fb%E7%9A%84%E5%80%BC2.%E8%AE%BEx%3Da%2F%28b%2Bc%29%3Db%2F%28a%2Bc%29%3Dc%2F%28b%2Ba%29%2C%E6%B1%82x%E7%9A%84%E5%80%BC3.%E5%B7%B2%E7%9F%A5p%E6%98%AF%E7%9B%B4%E7%BA%BFAB%E4%B8%8A%E4%B8%80%E7%82%B9AP%3APB%3D3%3A5%2C%E6%B1%82AB%EF%BC%9APB%E7%9A%84%E5%80%BC)
数学题,快写清过程,谢谢1.已知(a-2b)/b=5/3求(a+b)/b的值2.设x=a/(b+c)=b/(a+c)=c/(b+a),求x的值3.已知p是直线AB上一点AP:PB=3:5,求AB:PB的值
数学题,快写清过程,谢谢
1.已知(a-2b)/b=5/3求(a+b)/b的值
2.设x=a/(b+c)=b/(a+c)=c/(b+a),求x的值
3.已知p是直线AB上一点AP:PB=3:5,求AB:PB的值
数学题,快写清过程,谢谢1.已知(a-2b)/b=5/3求(a+b)/b的值2.设x=a/(b+c)=b/(a+c)=c/(b+a),求x的值3.已知p是直线AB上一点AP:PB=3:5,求AB:PB的值
1.
(a-2b)/b=5/3
a/b-2=5/3
a/b=2+5/3
(a+b)/b=a/b+1=2+5/3+1=4又2/3
2.
x=a/(b+c)=b/(a+c)=c/(b+a)=(a+b+c)/(b+c+a+c+b+a)=(a+b+c)/[2(a+b+c)]=1/2
3.
AP:PB=3:5
AB:PB=(AP+PB):PB=(3+5):5=8:5
1、3(a-2b)=5b
3a-6b=5b
3a=11b
a=11b/3
(a+b)/b=(11b/3+b)/b=14/3
2、a/(b+c)=b/(a+c)
即b^2+bc=a^2+ac (1)
b/(a+c)=c/(b+a)
即c^2+ac=b^2+ab (2)
a/(b...
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1、3(a-2b)=5b
3a-6b=5b
3a=11b
a=11b/3
(a+b)/b=(11b/3+b)/b=14/3
2、a/(b+c)=b/(a+c)
即b^2+bc=a^2+ac (1)
b/(a+c)=c/(b+a)
即c^2+ac=b^2+ab (2)
a/(b+c)=c/(b+a)
即c^2+bc=a^2+ab (3)
(1)(2)(3)相加
b^2+bc+2c^2+ac+bc=2a^2+ac+b^2+2ab
化简c^2-a^2+bc-ab=0
(c-a)(c+a)+b(c-a)=0
(c-a)(a+b+c)=0
c=a或-(a+b)
当c=a,因为a/(b+c)=b/(a+c),
故a/(b+a)=b/(a+b),
a=b=c,x=1/2
当c=-(a+b),因为x=a/(b+c)=b/(a+c)=c/(b+a),
x=a/(-a)=b/(-b)=-1
综上,x=1/2或-1
3、设AP=3a,则PB=5a,
AB=AP+PB=8a
AB:PB=8a:5a=8:5
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1. (a-2b)/b = (a+b-3b)/b = (a+b)/b - 3 = 5/3
所以 (a+b)/b = 14/3
2. 将 x=a/(b+c)=b/(a+c)=c/(b+a) 取倒数
则有 (b+c)/a = (a+c)/b 两边同时乘以ab
即 a + b = -c 或 a = b
同理则有 ...
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1. (a-2b)/b = (a+b-3b)/b = (a+b)/b - 3 = 5/3
所以 (a+b)/b = 14/3
2. 将 x=a/(b+c)=b/(a+c)=c/(b+a) 取倒数
则有 (b+c)/a = (a+c)/b 两边同时乘以ab
即 a + b = -c 或 a = b
同理则有 b + c = -a 或 b = c
c + a = -b 或 a = c
所以 x = -1 或 1/2
3. AB:PB = (AP + BP):BP = AP:BP + 1 = 8:5
还可以设每份为x 则 AP = 3x BP =5x
即 AB = 8x
所以 AB:BP = 8:5
收起
1(a-2b)/b=5/3 3a-6b=5b a=(11/3)b代入(a+b)/b=4
2由等式得
a=(b+c)x
b/[(b+c)x+c]=c/[b+(b+c)x最后变化的x=-1
3设AP=3x PB=5x
8:5或2:5