问题 解答题
阅读材料:
如果x1,x2是一元二次方程ax2+bx+c=0(a≠0)的两根,那么有x1+x2=-
b
a
x1-x2=
c
a
.这是一元二次方程根与系数的关系,我们利用它可以解题,例x1,x2是方程x2+6x-3=0的两根,求x12+x22的值.解法可以这样:x1+x2=-6,x1-x2=-3,则x12+x22=(x1+x22-2x1x2=(-6)2-2×(-3)=42.
请你根据以上解法解答下题:
(1)已知x1,x2是方程x2-4x+2=0的两根,求:(x1-x22的值;
(2)已知关于x的方程x2-6x+p2-2p+5=0的一个根是2,求方程的另一个根和p的值.
答案

(1)∵x1,x2是方程x2-4x+2=0的两根,

∴x1+x2=4,x1•x2=2,

∴(x1-x22=(x1+x22-4x1x2=42-4×2=8;

(2)由题意得,x1+x2=6,x1•x2=p2-2p+5,

∵x1=2,∴x2=4,

∴p2-2p-3=0,

解得,p=3或p=-1.

单项选择题 共用题干题
阅读理解

Just before midnight, six University of Cincinnati students were watching TV in an on-campus apartment when three men burst through the door. While one of the intruders pointed a gun at the group, the other two scooped up $4,400 worth of laptops, cell phones, video games and cash. Once they had what they wanted, the trio fled into the night.

Furious, the students chased down and tackled one of the burglars -- the one with the gun. In the struggle, it went off, and a bullet grazed a student's leg. His friends piled on the gunman and held him until police showed up.

By the next day, the injured young man was back in his apartment, and the suspect was in jail, charged with burglary, felonious assault and receiving stolen property. But how did the men manage to storm into an on-campus residence that November night in the first place? Simple: Students told police the building's main doors hadn't latched properly for days.

As parents confront ballooning college costs and shrinking acceptance rates, they are finding themselves with an even bigger, more basic problem: Which campuses are safe? Colleges seem like idyllic and secure places, and for the most part, they are. But ivy-covered walls can't keep out every bad element. This country's 6,000 colleges and universities report some 40,000 burglaries, 3,700 forcible sex offenses, 7,000 aggravated assaults and 48 murders a year. Other hazards -- fires, binge-drinking, mental-health problems -- are also on the rise.

Of course, that's not what parents and students see on America's serene campuses. There's a false sense of security, says Harry Nolan, a safety consultant in New York City. "Students see guards patrolling at night or a video camera monitoring the dorm entrance and think, nothing bad can happen to me," he explains. "People don't know that safety controls are often very lax."

小题1:What did the students do after the burglars fled into the night?

A.They stood there in surprise.

B.They ran after the burglars at once.

C.They waited for the police.

D.They phoned their teacher.小题2:What does the underlined word “latched” in the third paragraph probably mean?

A.watched

B.fixed

C.locked

D.kept小题3:What worries parents most except ballooning college costs and shrinking acceptance rates?

A.Their children’s grades in the universities or colleges.

B.Their children’s safety in the universities or colleges.

C.Their children’s behavior in the universities or colleges.

D.Their children’s relationship with classmates in the universities or colleges.小题4:Which is right according to the passage?

A.Their children’s grades in are high.

B.Their children’s safety in the universities or colleges will be mornitored well.

C.The universities or colleges don’t pay much attention to the children.

D.The universities or colleges are not key educational departments in the local area.