几道数学题,不难【分解因式一：x^4-46x^2+25 二：(x+y)^2+10(x+y)+25 三：2x^2+2x+0

1 x^4-46x^2+25
=(x^4-10x^2+25)-36x^2
=(x^2-5)^2-(6x)^2
=(x^2+6x-5)(x^2-6x-5)
=(x^2+6x-5)(x-5)(x-1)
=(x+3-√14)(x+3+√14)(x-5)(x-1)
2
(x+y)^2+10(x+y)+25 =(x+y+5)^2
3
2x^2+2x+0.5=2(x^2+x+1/4)=2(x+1/2)^2
4
9x^2+16xy+4y^2 =16x^2+16xy+4y^2-7x^2
=(4x+2y)^2-7x^2=(4x+2y-√7x)(4x+2y+√7x）
1
分式（x-1）/（2x+1) 有意义需 2x+1≠0,即x≠-1/2
2
3x+2是分母吧,应该括起来
5/（3x+2）>有意义,
需 5/（3x+2）>0 ==>3x+2>0 ==》x>-2/3

x^4-46x^2+25=(x^2-13+6√56)(x^2+13+6√56)
：(x+y)^2+10(x+y)+25 =(x+y+5)^2
2x^2+2x+0.5=1/2(4x^2+4x+1)=1/2(2x+1)^2
9x^2+16xy+4y^2 不能分解
如果9x^2+12xy+4y^2=（3x+2y）^2
分式x-1/2x+1 有意义 ...

1. x^4 -46x^2 +25
=(x^2 -5)^2 -36x^2
=(x^2-5+6x)(x^2-5-6x)
2. (x+y)^2+10(x+y)+25
= [(X+Y)+5]^2
3. 2x^2+2x+0.5
= 2(X^2+X+0.25)
= 2(X+0.5)^2
4. 9x^2+16xy+4y^2
...

不会