下列各算式中,合并同类项正确的是( )
A:x2+x2=2x2
B:x2+x2=x4
C:2x2﹣x2=2
D:2x2﹣x2=2x
下列句子中,划线的成语使用恰当的一项是( )
①____ What's your friend's name? A.Yes, she is.
②____ Does she have long hair? B.Yes, they are.
③____ Are they good friends? C.He's short.
④____ Is your brother tall or short? D.Yes, she does.
⑤____ Is she thin? E.Liu Tong.
下列说法正确的是( )
如图坐标平面上有一透明片,透明片上有一拋物线及一点P,且拋物线为二次函数y=x2的图形,P的坐标(2,4)。若将此透明片向右、向上移动后,得拋物线的顶点坐标为(7,2),则此时P的坐标为 ( )