3 math problems, solve, solve 3 math problems

and 1/4l, which is 5/4l, i.e. 5 4, 5 4 12 = 60 4, i.e. 15

2. The unknown number is set to x, x 2 3 is written as 3 2 5 12, that is, x 3 2 5 12, x 2 3 = 5 12, multiply 3 2 on both sides at the same time, and get x 5 8, that is, the original question is 5 8 2 3 15 16

3h (hour) completed 24, since the question is how long does it take for 10 cartons, then, in each carton unit, calculate that each carton took 1 36h, 1 36 10 10 36 5 18, that is, the final answer, 10 cartons take 5 18 hours. Wish.

1 1 and 1/4 multiplied by 12 equals 15 liters.

2 5/12 multiplied by 3/2 equals 5/8 Divide 5 8 by 2 3 The result is 15 16

3 24 divided by 2 3 equals 36 36 divided by 10 equals 3 and 3 fifths.

The first question (5 4 * 12 = 15 1 liter), the second question ((5 12 * 3 2) * 3 2 = 15 16), the third question (2 3 times 60 divided by 24 times 10 equals 11 40 hours).

15 1l5 1l12 divided by 2/3 equals 5/8

5/8 divided by 2/3 equals 16/15

1. Because ap=ab, then b= apb=2 c, and because apb= c+ pac then pac= c, then ap=pc, so ab=bp=ap=pc, so the triangle abp is an equilateral triangle, then bap= b=2 c=2 pac, so pac=1 3 bac

2. After turning 45 degrees, AD' overlaps with the diagonal AC. Let d'c' intersect bc e, then: d'e=d'c=2 2-2.

The shaded part is made up of two congruent right triangles: ad'e and ace. The area of the triangle ad'e is equal to ad'*d'e 2.

So, shaded area = 2 * (2 2-2) = 4 2-4.

The third question is questionable: from 1951 to 2011, a total of 60 years, how can it be a mu per year to reduce the mu of land?

The answer is correct (first course).

I'm going to talk a fart when I'm done talking on the first floor.

The first question is d because there are a, b, ab, and empty sets.

The second question chooses c, the third question chooses b, the first one is wrong, it is not a set.

1,c²=ab-9=(6-b)b-9=-(b-3)^2;

c = 0, b = 3, a = 3 (the square number is not negative, c can only be zero) 2, I don't know what to prove, I didn't write it clearly.

3，x1+x2=2k+1>2 =>k>1/2;

x1*x2=k^2+1>1 =>k>0;

Discriminant = (2k+1) 2-4(k 2+1)>=0 =>k>=3 4;

So: k>=3 4

x1/x2=1/2 =>x2=2x1;

3x1=2k+1;

2(x1^2)=k^2+1

Solution: k=1, or k=7;

It seems that you have made a mistake in the question.

1, Xiao Ming, Xiao Jun, Xiao Fang and Xiao Hong made a thousand paper cranes together, Xiao Ming only made 7 13 of the total number of the other three, Xiao Jun only made 1 3 of the total number of the other three, Xiao Fang only made 11 29 of the total number of the other three, Xiao Hong made 15, how many thousand paper cranes did they made?

Solution: From "the number of things Xiao Ming did is 7 13 of the total number of the other three people", Xiao Ming made 7 20 of the total;

From "the number of small armies is 1 3 of the total number of the other three people", the small army makes 1 4 of the total;

From "the number of things Xiao Fang did was 11 29 of the total number of the other three people", Xiao Fang made 11 40 of the total;

So, Xiaohong makes 1 - 7 20 + 1 4 + 11 40) = 5 40 = 1 8

Little Red made 15 of them, and the total number was 15*8 = 120

Xiao Ming made 42 of them.

Xiaojun made 30 of them.

Xiao Fang made 33 of them.

2. It took 9 hours for a car to go from point A to point B and then return to point A immediately; Travel 100 kilometers per hour on the way to the beginning and 80 kilometers per hour on the return. How many kilometers are the two places apart?

9 1 100 + 1 80) = 400 km.

3. A and B cars drive out from the east and west stations at the same time, and the speed ratio of A and B cars is 8:7; After the two cars met, car B traveled 15 kilometers per hour more than before, and the result was that both cars arrived at their destination at the same time. Q: How many kilometers does car A travel per hour?

The time before and after the two cars meet is equal:

Car A speed before the encounter 8V B car speed 7V - this is proportional to the distance.

After the encounter, car A speed 8V car B speed 7V+15 --car A walks the distance traveled by car B before the meeting.

8v ： 7v = 7v+15) ：8v

64 - 49)v = 7 * 15

The solution yields v = 15

A car speed 8V = 120 km/h.

BCar speed 7V = 105 km/h.

Wednesday, 6, 7, 8, 9, 10, 11, December 4 * 31 + 3 * 30 = 213 days, 213% 7 = 3, December 31, 2011 is Saturday, 2012 New Year's Day is Sunday.

2012-1949=63, 2012 is the 63rd anniversary.

There will be a holiday on July 10, 31-9 days in July and 31 days in August, with a total of 53 days of vacation.

Question 1: First calculate how many days there are from June 1st to New Year's Day, this is to subtract the day of June 1st from the day of New Year's Day, remember, after subtracting, it will take +1 day, divide this number of days by 7, you can get an integer and a remainder, the integer is the number of weeks to pass, don't worry about it, after that, as long as the remainder is on Wednesday + the remainder is the day of the week, the answer is Sunday.

Question 2: 2012-1949 + 1 = 64 years.

Question 3: (31-10+1) (this is the number of days off in July) + 31 (this is the number of days in August) = 53 days.