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190415
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# is one of the ways of adding, subtracting, multiplying and dividing. What kind of operation does # represent?
1: a*(a#a)=0 is true for any a.
2: a#(b#c)=(a#b)#c
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190415
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Is |2X-Y|=|2Y-X|？
1：X=Y
2：Y > 0
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190321
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The equation of the circle $$O_1$$ is $$x^2+y^2=4$$. The equation for $$O_2$$ is $$(x-a)^2+(y-b)^2 = 4$$. a and b are constants.$$a^2+b^2 = 4$$ . The two circles intersect on line l What is the equation of the line?
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190415
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MY*CD=12. BX*AC=?
1:BX=3MY
2:AC=5CD
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190321 还原机经选题: 数论&代数
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n is a three-digit number. Is n odd?
1: The sum of the three digits of n is odd.
2: The sum of the hundreds and the unit digit of n is twice of the tens digit.
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190321
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A student wants to choose two arbitrary letters from the 26 letters of a-z. How many ways for him to achieve his goal?
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190415
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$$\frac{1}{n}$$ < $$\frac{1}{31}$$ < $$\frac{1}{32}$$ < $$\frac{1}{33}$$ < $$\frac{1}{n-1}$$.n=?
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190415
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f(x)=1-x+$$x^{2}$$-$$x^{3}$$+$$x^{4}$$-$$x^{5}$$.f(3)=?
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190415
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$$a_1$$=4,$$a_n$$=2$$a_{n+1}$$,$$a_8$$=?
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190310
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Someone poured 1m^3 of water into a cuboid. What was the height of water in the cuboid?
1: The height of the cuboid is 2m.
2: The length and width of the cuboid are both 4m.
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190310
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The product of three positive numbers,$$2^4$$,x,$$5^3$$ , is a multiple of $$10^4$$. What is the minimum value of x?
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190415
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Quadrilateral ABCD is a square. The triangle BCE is an equilateral triangle. BC=10. DE=？
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190415
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The price of the class A computer is reduced by 20% to $2000. After a 25% increase in the price of the class B computer, the price will be $2000. What is the sum of the original prices of class A and class B computers?
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190310
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$$\frac{(n+9)!}{(n+10)!+(n+9)!} = \frac{1}{4!} n$$=?
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190310
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It took 15 minutes for a person to ride a bicycle from A to B. It took 25 minutes from B to A. The distance between A and B is 2km. What was the average speed of this person?
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190310
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$$(9^{900}+3^{1800})^2$$ =?
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190310
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ABCD is a square, the length of which is 10. DE is a quarter arc with C as the center and CD as the radius. EF is a quarter arc with B as the center and BE as the radius. FG is a quarter arc with A as the center AF as the radius. GH is a quarter arc with D as the center DG as the radius. What is the total length of arcs DE + EF + FG + GH?
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190310
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The general term of the sequence of equal difference numbers is $$a_{n+1} = a_{n} +7$$.$$ \sum^{20}_{i=1} a_{i} = 1530$$.$$s_4$$=?
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190310
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∠DAB=60°,∠ABC=75°,∠BCD=90°. BC=CD=x. What is the circumference of quadrilateral ABCD?
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190310
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The radius of a balloon was x. After air letting out, the volume was reduced by 48.8%. If the balloon is always sphere. What's the functional relationship between the radius r after leaking and the original radius x?
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