Question

几道数学题目，请大家帮我啊＝ ＝泪..

1.若x＾2－mx+n=(x-1)(x-3),求m，n的值．
2.利用简便方法计算
（1）3.167*1.258+1.258*（-4.167)+11*1.258
(2)-2/3*2/3+4/9*(-8)
(3)2008*57+2008*22+2008*21

大家给个过程吧，感谢大家，泪＝ ＝

Answer 1

1.(x-1)(x-3)=x^2-4x+3
对比得-m=-4,m=4;n=3
2.(1).原式=1.258*(3.167+11-4.167)
=1.258*10
=12.58
(2).原式=-4/9+4/9*(-8)
=4/9*(-1-8)
=4/9*（-9）
=-4
(3).原式=2008*（57+22+210
=200800

Answer 2

x＾2－mx+n=(x-1)(x-3)＝x＾2－3x-x+3=x＾2-4x+3
so m=4 n=3

（1）3.167*1.258+1.258*（-4.167)+11*1.258
=1.258*(3.167-4.167+11)
=12.58
(2)-2/3*2/3+4/9*(-8)
=-1-1/18
=-19/18
(3)2008*57+2008*22+2008*21
=2008*(57+22+21)
=200800

Answer 3

1. (x-1)(x-3)=x＾2-4x+3 所以m=4 n=3
2. 1.258*(3.167-4.167+11)=1.258*10=12.58
4/9*(-1-8)=-4
2008*(57+22+21)=20080

Answer 4

1 （x-1)(x-3)=X＾2-4x+4
代入m=4 n=4
1(1)=1.258*(3.167-4.167+11)
=1.258*10
=12.58
(2)=-4/9+4/9*(-8)
=4/9*(-1)+4/9*(-8)
=4/9*(-1-8)
=4/9*(-9)
=-4
(3)=2008*(57+22+21)
=2008*100
=200800

Answer 5

2008*(57+22+21)