一些常见的数学题3q very much
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一些常见的数学题3q very much
一些常见的数学题
3q very much
一些常见的数学题3q very much
1/(x^2-y^2)+2/(x-y)^2
=1/(x+y)(x-y)+2/(x-y)^2
=(x-y+2(x+y))/(x+y)(x-y)^2
=(3x+y)/(x+y)(x-y)^2
1.
x/(x-3)-2=-3/(3-x)
x/(x-3)-3/(x-3)-2=0
-2=0无解
2.
(x+1)(x-1)+2(x-1)^2=0
(x-1)(x+1+2x-2)=0
(x-1)(3x-1)=0
x=1,1/3
又x-1不为0
则x=1/3
3.
(5x-1)^2-(3x-2)^2=0
(5x-1-(3x-2))(5x-1+3x-2)=0
(2x+1)(8x-3)=0
x=-1/2,3/8
4.
7x^2+2x=0
x(7x+2)=0
x=0,-2/7
5.
(2x-5)^2-x^2=0
(2x-5-x)(2x-5+x)=0
(x-5)(3x-5)=0
x=5,3/5
x^2/25-y^2/16
=(x/5-y/4)(x/5+y/4)
计算：
1/(x^2-y^2)+2/(x-y)^2
=1/[(x+y)(x-y)]+2/(x-y)^2
=(x-y)/[(x+y)(x-y)^2]+2(x+y)/[(x+y)(x-y)^2]
=(x-y+2x+2y)/[(x+y)(x-y)^2]
=(3x+y)/[(x+y)(x-y)^2]
解方程：
1.
x/(x-3)-2=(-3...
全部展开
计算：
1/(x^2-y^2)+2/(x-y)^2
=1/[(x+y)(x-y)]+2/(x-y)^2
=(x-y)/[(x+y)(x-y)^2]+2(x+y)/[(x+y)(x-y)^2]
=(x-y+2x+2y)/[(x+y)(x-y)^2]
=(3x+y)/[(x+y)(x-y)^2]
解方程：
1.
x/(x-3)-2=(-3)/(3-x)
(x-3)/(x-3)=2
1=2
方程错了。。。
2.
(x+1)/(x^2-2x+1)+2/(x-1)=0
(x+1)/(x-1)^2+2/(x-1)=0
(x+1)+2(x-1)=0
x+1+2x-2=0
3x=1
x=1/3
3.
(3x-2)^2=(1-5x)^2
3x-2=1-5x
或3x-2=-(1-5x)
8x=3
或2x=-1
解得：
x=3/8或x=-1/2
4.
7x^2+2x=0
x(7x+2)=0
x=0或7x+2=0
解得：
x=0或x=-2/7
5.
x^2=(2x-5)^2
x=2x-5或x=-(2x-5)
解得：
x=5或x=5/3
因式分
x^2/25-y^2/16
=(x/5)^2-(y/4)^2
=(x/5+y/4)(x/5-y/4)
收起
计算：
1/(x^2-y^2)+2/(x-y)^2
=1/[(x+y)(x-y)]+2/(x-y)^2
=(x-y)/[(x+y)(x-y)^2]+2(x+y)/[(x+y)(x-y)^2]
=(x-y+2x+2y)/[(x+y)(x-y)^2]
=(3x+y)/[(x+y)(x-y)^2]
1.
x/(x-3)-2=-3/(3-x)
全部展开
计算：
1/(x^2-y^2)+2/(x-y)^2
=1/[(x+y)(x-y)]+2/(x-y)^2
=(x-y)/[(x+y)(x-y)^2]+2(x+y)/[(x+y)(x-y)^2]
=(x-y+2x+2y)/[(x+y)(x-y)^2]
=(3x+y)/[(x+y)(x-y)^2]
1.
x/(x-3)-2=-3/(3-x)
x/(x-3)-3/(x-3)-2=0
-2=0无解
2.
(x+1)(x-1)+2(x-1)^2=0
(x-1)(x+1+2x-2)=0
(x-1)(3x-1)=0
x=1,1/3
又x-1不为0
则x=1/3
3.
(5x-1)^2-(3x-2)^2=0
(5x-1-(3x-2))(5x-1+3x-2)=0
(2x+1)(8x-3)=0
x=-1/2,3/8
4.
7x^2+2x=0
x(7x+2)=0
x=0,-2/7
5.
(2x-5)^2-x^2=0
(2x-5-x)(2x-5+x)=0
(x-5)(3x-5)=0
x=5,3/5
x^2/25-y^2/16
=(x/5-y/4)(x/5+y/4)
收起