抛物线y=x2+2x-3的对称轴是( )
A:直线x=1
B:直线x=-1
C:直线x=-2
D:直线x=-3
⑴May I take your picture?____ A. No, I hurt my arm.
⑵Are you okay?____ B. Yes, he is.
⑶Don't draw or write on the wall.____ C. I'm walking to the hotel.
⑷Is Danny busy?____ D. Sure!
⑸What are you doing?____ E. OK, I'm sorry.
x
3
﹣2
4
2
y
-2 3
0
﹣4
22
若 3m-2n2n+1与3是同类最简二次根式,则求mn的值.
Put your hand your desk.