数学题,因式分解!速度!
来源:百度知道 编辑:UC知道 时间:2024/05/01 02:24:43
1.已知x+3y=10,求(x^2-9y^2)/(x-3y)的值.
2. a^2(a-3)-(a-3)
3.如果 x^2-5x-6=(x+1)(x-m) 则m的值为
4.已知4a^2+4a+b^2-6b+10=0,则a^3b-ab^3=
5.如果m^2-4mn+4n^2=0,求(m^2+n^2)/mn的值
第1和5题要过程!过程!
2. a^2(a-3)-(a-3)
3.如果 x^2-5x-6=(x+1)(x-m) 则m的值为
4.已知4a^2+4a+b^2-6b+10=0,则a^3b-ab^3=
5.如果m^2-4mn+4n^2=0,求(m^2+n^2)/mn的值
第1和5题要过程!过程!
1.
(x^2-9y^2)/(x-3y)
=(x-3y)(x+3y)/(x-3y)
=x+3y
=10
2.
a^2(a-3)-(a-3)
=(a^2-1)(a-3)
=(a-1)(a+1)(a-3)
3.
根据题意得:
x^2-5x-6=(x+1)(x-6)
即:
m=6
4.
4a^2+4a+b^2-6b+10=0
(4a^2+4a+1)-1+(b^2-6b+9)-9+10=0
(2a+1)^2-1+(b-3)^2-9+10=0
(2a+1)^2+(b-3)^2=0
(2a+1)^2=0
a=-1/2
(b-3)^2=0
b=3
a^3b-ab^3
=ab(a^2-b^2)
=ab(a-b)(a+b)
=(-1/2)*3*(-1/2-3)*(-1/2+3)
=(-3/2)*(-7/2)*(5/2)
=105/8
5.
m^2-4mn+4n^2=0
(m-2n)^2=0
m=2n
(m^2+n^2)/mn
=[(2n)^2+n^2]/(2n*n)
=(4n^2+n^2)/2n^2
=5n^2/2n^2
=5/2
10
(a-3)(a+1)(a-1)
6
-95/8
3/2
10
(a-3)(a+1)(a-1)
6
-95/8
3/2
10
(a-3)(a+1)(a-1)
6
-95/8
3/2