挑战习题
1/5单选题
难度:

1.

下列函数关系式中,是二次函数的是(  )


A

y=x3-2x2-1

B

y=x2

C

D

y=x+1

提示1:
PHA+5qC55o2u5LqM5qyh5Ye95pWw55qE5a6a5LmJ5p2h5Lu25a+55Zub5Liq6YCJ6aG56L+b6KGM6YCQ5LiA5YiG5p6Q5Y2z5Y+v77yOPC9wPg==
正确答案:Qg==
PHA+6Kej77yaQeOAgeiHquWPmOmHj+eahOacgOmrmOasoeaVsOaYrzPvvIzplJnor6/vvJs8YnI+QuOAgeato+ehru+8m+WxnuS6juS6jOasoeWHveaVsOeahOS4gOiIrOW9ouW8j++8mzxicj5D44CB5Y6f5Ye95pWw5Y+v5YyW5Li677yaeT0yeDxzdXA+LTI8L3N1cD4tM++8jOiHquWPmOmHj+eahOacgOmrmOasoeaVsOaYry0y77yM6ZSZ6K+v77ybPGJyPkTjgIHoh6rlj5jph4/nmoTmnIDpq5jmrKHmlbDmmK8x77yM6ZSZ6K+v77yOPGJyPuaVhemAiULvvI48L3A+