题目在此

一、计算
1、2 .——正好消去y,2x/x=2
2、2 .——正好消去x^2,2xy/xy=2
3、3/2.——正好可以提出3,3(a+1)/2(a+1)=3/2
4、(x-3y)/(x-y)^2
5、-(a+b)/(2a-2b)
6、(x^2+y^2)/(x+y)
7、x/(x-1)
8、x^2/(x+2y)
9、变下1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+1)(x+3)
=[(x+3)+(x+1)+(x+2)]/(x+1)(x+2)(x+3)
=3(x+2)/(x+1)(x+2)(x+3)
=3/(x^2+4x+3)
10、变[(x+y)^2/(x-y)]*[(x-y)^2/(x+y)]
=(x+y)(x-y)
=x^2-y^2
11、[-4ab/(a+b)^2(a-b)^2]*[-(a+b)(a-b)/(2b)]=2a/(a^2-b^2)
12、=(y-z)/(x-y)(y-z)=1/(x-y)
13、(x-1)/(x+1)(x+2)-6/(x+1)(x-2)-(x-10)/(x+2)(x-2)
=[(x^2-3x+2)-(6x+2)-(x^2-9x-10)]/(x+1)(x+2)(x-2)
=10/(x^3-3x^2-4)
二、解方程
1、x=2(x-3)+3 2、x-5=2x-5 3、(x-2)^2-16=x^2-4
x=3 x=0 -4x-12=-4 → x=-2 (分母为0,无解)
4、7x-7+x+1=0 5、15x-12=4x+10-3x+6 6、2x^2-8x+16=2x^2-4x
x=-3/4 14x=28 → x=2(同3无解) x=4