化简下列各式：

（1）5x⁴+3x²y-10-3x²+x-1;                                           （2）p²+3pq+6-8p²+pq ;

（3）（7y-3z）-（8y-5z）;            

（4）-(a⁵-6b)-(-7+3b)

（5）2（2a²+9b）+3（-5a²-4b）；

（6）-3（2x²-xy）+4（x²+xy-6）.

用消元法解下列线性方程组:-|||- x1+3x2+5x3-4x4 =1, x1+3x2+2x3-2x4+x5=-1, x1-2x2+x3-x4-x5=3, x

已知两个线性变换： ) (y)_(1)=2(x)_(1)+(x)_(2) (y)_(2)=3(x)_(1)-(x)_(2)+2(x)_(3) (y)_(3)=

[主观题]求函数y=x3-3x2-9x＋1的极值．

2.解方程组 ) (x)_(1)+(x)_(2)+(x)_(3) (x)_(1)+(x)_(2)-(x)_(3)-(x)_(4)=1 5(x)_(1)+5(

[问答题]求x3y″′+x2y″-4xy′=3x2的通解。

[问答题]求x3y″′+x2y″-4xy′=3x2的通解。

[问答题]求x3y″′+x2y″-4xy′=3x2的通解。

10.已知线性变换-|||- ) (x)_(1)=2(y)_(1)+2(y)_(2)+(y)_(3) (x)_(2)=3(y)_(1)+(y)_(2)+5(y

解方程_(2)-3(x)_(3)+4(x)_(4)=-5-|||-x1- 2x3+324 =-4-|||-(x)_(1)+2(x)_(2)-5(x)_(4)=1

4.已知两个线性变换:-|||- ) (y)_(1)=(x)_(1)+2(x)_(2)+3(x)_(3) (y)_(2)=-(x)_(1)+3(x)_(2)-