A factory a and B two workshops, last year plans to complete the tax and profit of 7.5 million yuan, the result of a workshop 15% over the plan, B workshop 10% over the plan, the two workshops jointly complete the tax and profit of 8.45 million yuan, ask these two workshops last year to complete the tax and profit of how many million yuan?

A factory a and B two workshops, last year plans to complete the tax and profit of 7.5 million yuan, the result of a workshop 15% over the plan, B workshop 10% over the plan, the two workshops jointly complete the tax and profit of 8.45 million yuan, ask these two workshops last year to complete the tax and profit of how many million yuan?

Last year, the two workshops completed tax and profit x, y 10000 yuan, x + y = 750, 1.15x + 1.1y = 845, x = 400, y = 350 respectively

The front tires of a bicycle will be scrapped after 9000 km, and the rear tires will be scrapped after 7000 km. The front and rear tires can be exchanged at the right time. How many km can a bicycle run with a pair of new tires at the same time?

Take the distance that each wheel can travel as "1", as if it needs to travel: (1 + 1) △ 19000 + 13000) = 2 △ 1663000 = 7875 (km). A: this pair of tires can travel 7875 km at most and should be scrapped

It is known that A-B = 4, the square of AB + C + 4 = 0, a + B =?

Because the square of AB + C = - 4, we can conclude that AB is negative, then AB is different sign,
So a is a positive number and B is a negative number,
A = 1, B = - 3
2．A＝2 B＝－2
3．A＝3 B＝－1
If the above solution is substituted into the original formula, only 2 is consistent, so a + B = 0
(we can ignore the value of C, which is just to prove that AB is negative.)

Junior High School Mathematical Olympiad (step in the rain)
A parallelogram efgh is inscribed in the square ABCD, and the four vertices of the parallelogram efgh are respectively on the four sides of the square. If the side length of the square is a, the minimum perimeter of the parallelogram efgh is obtained

L = 4 * under the root sign ((A-X) ^ 2 + (a-y) ^ 2) x + y = a (A-X) ^ 2 + (a-y) ^ 2 = 2A ^ 2-2a (x + y) + x ^ 2 + y ^ 2 = (x + y) ^ 2-2xy-2a (x + y) + 2A ^ 2 = ((x + y) - a) ^ 2 + A ^ 2-2xy = a ^ 2-2xy, find the minimum value, that is, find the maximum value of XY is less than or equal to ((x + y) / 2) ^ 2L = 2 * the root sign (3) a perimeter is twice

The number of the third grade Chinese interest group is 19 less than that of the mathematics interest group. If we want to make the number of the Chinese interest group 5 less than that of the mathematics interest group, how many people should be transferred from the mathematics group to the Chinese interest group?
It's five more

(19 + 5) △ 2 = 12 (person)

Fill in the operation symbol to make the following equation true
8 8 8 8 8 8 8 8=1000

[8*(8+8)-(8+8+8)/8]*8=1000 (8888-888)/8=1000,(8+888)/8+888=1000,(888+8)/8+888=1000 888+(8+888)/8=1000,888+(888+8)/8=1000,8+8+8+88+888=1000 8+8+8+888+88=1000,8+8+88+8+888=1000,8+8+88+888+8=1000 8+8+888...

Is it not difficult for the third grade of primary school to have Olympic math
I think it's very difficult

It's hard to see how the teacher teaches. The Mathematical Olympiad has its own rules. Only when the teacher teaches well, the students remember it. So learning the Mathematical Olympiad depends on the teacher (of course, students are very important, but we can't guarantee that everyone is a genius)

Does the third grade of primary school need to learn Olympiad Mathematics?

If the textbook is easy to learn, the problem-solving speed is fast, the correct rate is high, and you are interested in mathematics
It's best to have these talents, otherwise it's a burden

Xiaoming is 9 years old and his father is 36 years old. What does his father belong to?
No. the original question is: 1. Xiaoming is 9 years old and belongs to dragon. Dad is 36 years old. What does he belong to?
2. Xiao Ming's mother is also a dragon. How old is her mother?
3. Xiao Ming's grandfather is a horse. How old is his grandfather?

Twelve zodiac signs:
Zi rat, Chou Niu, Yin Hu, Mao Tu, Chen long, Si she, Wu Ma, Wei Yang, Shen Hou, you Ji, Xu Gou, Hai Zhu
one
36-9 = 27 years old = 24 years old + 3 years old = 20 years old + 3 years old
Before Chen Long: 3 years old = Chou Niu, Yin Hu, Mao Tu
Father is a cow
two
According to the actual life, mother should be twenty years older than Xiao Ming
9 + 24 = 33 years old
three
According to the actual life, grandfather should be sixty years older than Xiao Ming
Chen Longhou: Si snake, Wu Ma = 2 years old
(9-2) + 12 × 4 = 67 years old

Triangle ABC, ad ⊥ BC, ab = 8, BC = 6, AC = 7, De is the angle bisector of triangle abd, find De
The standard answer is four out of 151,

Let BD = x, DC = 6-x
In the triangle abd, ad square = 64-x square
In ACD, ad square = 49 - (6-2) square
So 64-x square = 49 - (6-2) square
The solution is x = 17 / 4
So BD = 17 / 4 ad = 7 / 4 times root 15
Then ad * BD = ed * AB (area)
So de = 4 / 151 of the root