在解题目：“当x=1949时，求代数式x2-4x+4x2-4÷x2-2xx+2-1x+1的值”时，聪聪认为x只要任取一个使原式有意义的值代入都有相同结果．你认为他说的有理吗？请说明理由．-数学

更多内容推荐

• 化简求值：(x2-16x2+8x+16+xx-4)÷1x2-16，其中x=2+1．-数学
• 请你先化简，再选取一个使原分式有意义，而你又喜欢的数代入求值：x3-x2x2-x．-数学
• 计算(1+1a)÷(1-1a)的结果为（）A．a+1a-1B．a-1a+1C．a2-1a2D．a2a2-1-数学
• Liu Yang became the first woman astronaut in China _____into space. ( )A．ravelB．travelledC．to travel
• The boy pretended when his parents entered the room.A．readingB．to readingC．to be readingD．having re
• She didn’t feel happy_____ in a block of apartments. She’d rather ______ in a traditional house.A．l
• ________at the restaurant with a wide variety of dishes served before, Bob didn’t want to eat there
• The officer gave orders that anyone_____ a gun should be reported to the police station.A．seen taki
• There is a small object _____ a pin on the desk.A．resemblingB．resembling withC．resembledD．resembled
• We don’t allow ___in the office. But you are allowed ____in the rest room. A．smoking, smokingB．to sm
• _________working all day long, he fell asleep as soon as he lay on the bed.A．Getting tired ofB．Gett
• （1）计算：（-a2bcd3）3÷2ad3•（-c2a）2；（2）aa-1÷a2-aa2-1-1a-1．-数学
• 计算：aa-1÷a2-aa2-1-1a-1-数学
• All students are requested to be present at the meeting ______ in the school auditorium at 1:30 pm.A
• 化简求值：a2+4a+4a+1÷(a-1-3a+1)，其中a=3．-数学
• The snow lasted a week, ________a serious traffic confusion in the whole area.A．causing B．causeC．to
• 化简求值：当x=﹣2时，=（）-八年级数学
• As a matter of fact,his remarks left me ______ about his real purpose. A．wonderedB．wonderC．to wonder
• The girl ________at the party yesterday is missing today.A．referring to B．refer toC．referred toD．to
• 若x=2005，则（）÷=（）。-八年级数学
• Would you be ______ to do me a favour, please?A．so kind as .B．too kindC．as kind asD．enough kind-英语
• ________not to miss the lecture at 2 p.m,Wang Dong left in a hurry.A．RemindingB．To remindC．RemindedD
• 先化简，再求值：(1+1x-2)÷(x2-2x+1x2-2x)，其中x=3．-数学
• He missed _______ when he was in Africa.A．killingB．to be killedC．to killD．being killed-高一英语
• 先化简再计算：x2-y2x-y-2x+y，其中x=3，y=2．-数学
• 先化简，再求值：(3aa+1-aa+1)•a2-1a，其中a=7+1-数学
• Canada is a country _____many different nationalities as well as one with foreign immigrants _____ t
• 先将x2-2xx+1•(1+1x)化简，然后请你自选一个合理的x值，求原式的值．-数学
• 先化简后求值：（a-b+4aba-b）（a+b-4aba+b），其中a=32，b=12．-数学
• 先化简，再求值：(x+2-5x-2)÷x-3x-2，其中x=5-3．-数学
• How to keep the homeless __________ with food and clothing is still under discussion．A．supplyingB．su
• There is a small group of words which even some native speakers and writers of English find ______.A
• _____ in every aspect of his company’s business, Paul made himself busy day and night.A．Being involv
• The chair looks rather hard, but in fact it is very comfortable to _______.A．sittingB．sit onC．sitD．
• 先化简再计算：÷（x-），其中x是一元二次方程x2-2x-2=0的正数根.-九年级数学
• _____for the damage to the house , Daisy had to pay a heavy fine. A Blaming B blamed C To blame D To
• On his way home, he found a wallet ____ on the ground, which he picked up and ____ in his schoolbag.
• 33．The famous singer is traveling across the country,_________her new album.A．classifyingB．expanding
• 先化简，再求值：a2-2ab+b2a2-b2÷（1a-1b），其中a=1+2，b=1-2．-数学
• Some people are sitting on the grass; others are walking along the lake, ______ .A．chatting and to l
• 已知x2+3x-1=0，求x-1x和x2+1x2的值．-数学
• 若ab=2，则a2-ab+b2a2+b2=______．-数学
• The police have collected some information the murder.A．connected toB．connected withC．connecting wit
• “Where Are We Going? Dad” is a Chinese reality TV show broadcast on Hunan Television, _____ 75 milli
• 已知10个数x1，x2，x3，…，x10中，x1=2，对于整数n＞1，有(n+1)xn=nxn-1，则x1x2=______，x2x3…x10=______．-数学
• People all around the world have been doing as much as they can ________the people in Afghanistan.A．
• ___ nice, the food was sold out soon.A．TastedB．TastingC．To tasteD．Being tasted-英语
• What difficulty will you have _______ people when you stay in a foreign country?A．understandingB．und
• 先化简再求值：a2-b2a2b-ab2÷(1+a2+b22ab)，a=7-11，b=-4+211．-数学
• 若b+1c=1，c+1a=1，求ab+1b的值．-数学