题干

二次函数y=3x2的图象向左平移2个单位,得到新的图象的二次函数表达式是(    )

A:y=3x2+2

B:y=(3x+2)2

C:y=3(x+2)2

D:y=3(x-2)2

上一题 下一题 0.0难度 选择题 更新时间:2019-01-30 06:00:58

答案(点此获取答案解析)

C

同类题1

阅读下面的短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

      Minnie was very popular with her friends. Every year, her classmates voted her as their favorite student and she was always 1  of having so many friends.

       One day the 10-­year­-old girl was caught talking and2in class and was ordered to stay back after school as a punishment. She had to help in the school3 for at least one hour. It is also a rule that once in a month the one getting4 could ask a friend to do that for him if he is busy. And of course, he had to5 the favor within the same month.

       It was the last day of that month and Minnie had promised to go to the airport and see her uncle Tom from New York while he was waiting for his connecting 6to Florida. She was sure someone would stand in for her out of 7.

        She turned to Peres, her best friend. But Peres said she had to coach her brother for his8 test. “The kid can't even calculate9 without my help.” She spent a lot of time talking about her brother's learning 10.

     “Morris, could you take my11 this afternoon?” Minnie asked another friend, who often stayed 12at school. “To help the librarian? I have to 13  my cousin's birthday with her family.” and then Morris 14.

        By now, Minnie began to15 if even one of her friends would agree to stay. She tried three more but all of them16. No one said “no”17, but everyone was giving his or her reason why they couldn't stay back for her.

      Finally, Minnie stayed to help the librarian, Mr. King. When he found her unhappy about being unable to keep her18 with her uncle, he allowed Minnie to 19, which turned her tears into a big smile. “You seem to have a lot of friends,” Mr. King said, “But you should 20 that a friend in need is a friend indeed.”

同类题3

阅读下面的文言文,回答小题。
扬江陵府曲江楼记
【宋】朱熹
      广汉张侯敬夫守荆州之明年,岁丰人和,幕府无事。常病其学门之外即阻高墉。乃凿门通道,以临白河,且为楼观以表其上。敬夫一日与客往而登焉,则大江重湖,萦纡渺弥;而西陵诸山,空濛晻①霭,又皆隐见出没于云空烟水之外。敬夫于是顾而叹曰:“此亦曲江公②所谓江陵郡城南楼者邪?昔公去相而守于此,其平居暇日,登临赋咏,盖皆翛然有出尘之想。至其伤时感事,则其心未尝一日不在于朝廷。而汲汲然惟恐其道之终不行也。悲夫!”乃书其扁曰“曲江之楼”,而以书来属予记之。
      予读敬夫之书,而知兹楼之胜。思得一与敬夫相从游于其上,瞻眺江山,览观形制,然后举酒相属以咏张公之诗而想见其人于千载之上庶有以慰夙心者。张公远矣,而读其书者,未尝不为之掩卷太息也。是则是非邪正之实,乃天理之固然,而人心之不可已者。登此楼者,于此亦可以反诸身,而自得之矣。
      予于此楼,既未得往寓目焉。无以写其山川风景、朝暮四时之变,如范公之书《岳阳》。独次第敬夫本语,而附以予之所感者如此。后有君子,得以览观焉。
                                                                                                                                                    (选自《朱熹诗文选译》,有删改)
      【注释】①晻:昏暗不明。②曲江公:张九龄,唐玄宗开元年间任宰相,后为李林甫所谮,贬为荆州刺史。曾作《登郡城南楼诗》。