Question

已知x+y=4,xy=-2分之1求x^5y^4+x^4y^5的值

Answer 1

1.x09x^5y^4+x^4y^5= x^4y^4（x+y）=( xy ) ^4（x+y）=(-1/2) ^4*4=1/4

2． (ax+b)(x^2-2x-1)得a+2b=0即a=-2b一次二项式只要满足这个条件就行.

3．(x-m)^2=x^2+nx+16分之1,则m=1/4,n=-1/2