数学CASE若分式方程x^2-1分之k-1减去x^2-x分之1=x^2+x分之k-5有增根x=-1,求K的值当x=2006时,(x+3)(x^2-3x+9)-(x-2)(x^2+2x+4)的值是已知x大于等于y,化简x+y-|x-y|=＿＿＿＿{5a^2+()-7}+{()a^2-4a+()}=a^2+2a+1(x-a)(x-b)

Question

数学CASE
若分式方程x^2-1分之k-1减去x^2-x分之1=x^2+x分之k-5有增根x=-1,求K的值
当x=2006时,(x+3)(x^2-3x+9)-(x-2)(x^2+2x+4)的值是_____
已知x大于等于y,化简x+y-|x-y|=＿＿＿＿
{5a^2+( )-7}+{( )a^2-4a+( )}=a^2+2a+1
(x-a)(x-b)=x^2+AX+B,则A=__B=___
设n为正整数,且x^2n=2,计算(3x^3n)^2-4(x^2)^2n的值

Answer 1

1.
通分有：
[x(k-1)-(x+1)-(k-5)(x-1)]/[x(x-1)(x+1)]=0
→x=(6-k)/3
∵有增根-1
∴有(6-k)/3=-1
k=9
2.根据立方差公式有
(x+3)(x²-3x+9)-(x-2)(x²+2x+4)=(x³+3³)-(x³-2³)=3³-2³
=27-8=19
3.
x≥y,所以|x-y|=x-y
x+y-(x-y)=2y
4.{5a^2+(6a)-7}+{(-4)a^2-4a+(8)}=a^2+2a+1
5.(x-a)(x-b)=x^2+AX+B,则A=__B=___
A=-(a+b),B=ab
6.设n为正整数,且x^2n=2,计算(3x^3n)^2-4(x^2)^2n的值
(3x^3n)^2-4(x^2)^2n=3^2 * x^6n-4*x^4n
=9*(x^2n)^3-4*(x^2n)^2=9*2^3-4*2^2=72-16=56