3x 4(x-3)=44

a=[1,1,1,1;2,3,-1,-1;3,2,1,1;3,6,-1,-1];>>b=[0;2;5;4];>>x=inv(a)*bx=0.61.3-2.2518e+162.2518e+16再问：我怎

那个=4真的是=4?还是+4?=4的话x4-4x3+9x2-10x+4=4+4的话x4-4x3+9x2-10x+8

x^2-3x+1=0x^2+1=3x同时除以xx+1/x=3所以x^2+1/x^2=(x+1/x)^2-2=3^2-2=7x^2/(x^4+x^2+1)=1/(x^2+1+1/x^2)=1/8

x+1/x=3,两边同时平方得到x^2+1/x^2+2=9所以x^2+1/x^2=7x^2/(x^4+x^2+1)=1/(x^2+1/x^2+1)=1/(7+1)=1/8

3x+20-25=x-403x-x=25-20-402x=-35x=-17.5

x^2/x^4+x^2+1=1/x^2+x^2+1x+1/x=3(x+1/x)^2=3^2=9x^2+1/x^2+2=9x^2+1/x^2=7则x^2+1/x^2+1=8即x^2/x^4+x^2+1=

x²+1=-3x两边平方x^4+2x²+1=9x²x^4+1=7x²两边平方x^8+2x^4+1=49x^4x^8+1=47x^4两边除以x^4x^4+1/x^

3.3X-1.2X4=8.4　　3.3X-4.8=8.4　　3.3x=8.4-4.8　　3.3x=3.6　　x=12/11　　18÷2X=3　　18=6x　　x=3

一式无法分解二式(x+1)*(x^2+x+1)*(x^2-x+1)三式无法分解

其实第n项=n*(n+1)=n^+n;则前n项的和为n(n+1)(2n+1)/6+n(n+1)/2=n(n+1)(n+2)/3.题目：带入即可得2010/3

增广矩阵=21-1113-21-3414-35-2r2-r1-r3,r1-2r30-75-950-75-9514-35-2r2-r1,r1*(-1/7),r3-4r101-5/79/7-5/70000

5式相加,3（x1+x2+x3+x4+x5）=1+5-5-3+2=0所以x1+x2+x3+x4+x5=0X1+X2+X3=5,X4+X5+X1=-3,两式相加：X1+（X1+X2+X3+X4+X5）=

x²+3x+1=0等式两边同除以xx+3+1/x=0x+1/x=-3x²+1/x²=(x+1/x)²-2=(-3)²-2=9-2=7x⁴+

x^2-3x+1=0x^2+1=3xx+1/x=3(x+1/x)^2=9x^2+1/x^2+2=9x^2+1/x^2=7(x^2+1/x^2)^2=49x^4+1/x^4+2=49x^4+1/x^4=

x²-3x+1=0可以得出x≠0两边同除以x得x-3+1/x=0即x+1/x=3x²+1/x²=（x+1/x）²-2=7x⁴+1/x⁴=

x+1/x=3两边平方x^2+2*x*1/x+1/x^2=3^2x^2+2+1/x^2=9x^2+1/x^2=7x^2/(x^4+x^2+1)上下除以x^2=1/(x^2+1+1/x^2)=1/(7+

(1)x-1/x=-2(2)x2+1/x2=1/2（3）x4+1/x4=1/4再问：能告诉我过程吗？再答：（1）已知x2+2x-1=0则x²-1=2x等式两边同时除以x不等于0的数得：x-1

1-2x-56=3-x4-2x+4x=3-1+562x=58x=58/2

x平方-3x+1=0二边同除以xx-3+1/x=0x+1/x=3x^2+1/x^2=(x+1/x)^2-2=3^2-2=7x^4+1/x^4=(x^2+1/x^2)^2-2=7^2-2=47