A={2x2-ax+b=0}，B={bx2+（a+2）x+5+b=0}，且A交B={2分之1}，求A并B？

急求，最迟今天晚上！！
还有一道英语题：短文改错
1.This is my first week in senior middle school.Now Iam
2.study in a new school and none my old friends
3.have come to this school with me.I felt very lonely by the begginning.
4.But two days ago,I made friend with one of my new
5.classmates.His home was very close to the school,so he
6.can go home every day.He invited me have supper in
7.his home on yesterday.His mothor is a very kind-hearted
8.woman.She said that it was very importantly to have some
9.good friends in senior middle school.I am sure I will

已知a>0,b>0,若关于x的方程x2+ax+2b=0与x2+2bx+a=a都有实数根，则a+b的最小值为多少 开口向下的抛物线y=ax^2+bx+c,与x轴较于A(x1,0),B(x2,0),(x1<x2)两点，与y轴交于点C(0,5),若a+b+c=0, 已知a>b>c且a+b+c=0，求证：ax平方+2bx+c=0的根x1.x2满足根号3〈|x1-x2|<2根号3 设集合U=R,集合A={x|x^2+ax-12=0},B={x|x2+bx+b2-28=0}, ax-3a=bx+b解方程 求解关于X的方程:ax-b=bx+a A,B,C互不等,AX方+BX+C=0,BX方+CX+A=0,CX方+CX方+AX+BX=0有一公根, (ax-b)^2=ax-b (a.b为常数,a≠0) a={x2-ax+a-1=0} b={x2+3x-2a2+4=0} a,b是正数，并且抛物线y=x2+ax+2b和y=x2+2bx+a都与轴有公共点，则a2+b2的最小值是多少?