Urgent (7 19:48:44) As shown in the figure, the east-west street and the South-North Street intersect at o point. A goes from west to east along the East-West Road, and the speed is 4m / S; B goes from south to north along the North-South Road, and the speed is 3m / s. when B goes through o point and goes on for 50m, a just goes through o point. Find out the position of the two when they are 85m apart after passing o point  

Urgent (7 19:48:44) As shown in the figure, the east-west street and the South-North Street intersect at o point. A goes from west to east along the East-West Road, and the speed is 4m / S; B goes from south to north along the North-South Road, and the speed is 3m / s. when B goes through o point and goes on for 50m, a just goes through o point. Find out the position of the two when they are 85m apart after passing o point  

Because the hypotenuse of the triangle is 85, let B walk for another x seconds, the distance between B and O is 50 + 3x, and the distance between a and O is 4x
Get the equation
Square of X + square of (50 + 3x) = square of 85

Fraction (11:18:18:5)
Do not change the value of the fraction so that the coefficients of the highest order terms of the numerator and denominator of the following fractions are positive numbers:
（1）2-a-a·a/-a·a·a+3a-1
（2）1-x-x·x/1+x·x+x·x·x
（3）-1+a·a·a/a·a-a+1

(1) This problem only needs to multiply the numerator and denominator by (- 1) at the same time
(2) The denominator of this problem does not need to be changed. The numerator needs to be multiplied by (- 1), so just multiply by (- 1) and then add a negative sign in front of the whole fraction
(3) After this formula is written, it already meets the condition that "the coefficients of the highest order terms of the numerator and denominator are all positive numbers". If you look at it awkwardly, you can change the order of the cube of a and (- 1), which is very satisfying

1/5x+3/20x=51

1/5x+3/20x=51
4/20x+3/20x=51
7/20x=51
x=1020/7

If a times a can be regarded as the area of a square with side length a, then what is the geometric meaning of the second power B of a?

It can represent the volume of a cuboid with a bottom area of a ^ 2 and a height of B

In proportion, what is the result of subtracting the product of two external terms from the product of two internal terms

In proportion, the product of two inner terms is equal to the product of two outer terms. This is the definition of proportion, so their subtraction must be equal to zero

1. A and B stores buy the same commodity at the same unit price of 200 yuan. Store a sells it at a 30% profit increase, while store B sells it at a 20% profit increase. The number of products sold by store B is twice that of store a, and the total profit is 8000 yuan more than that of store A. how many products have been sold by store a and store B
2. There are 10kg alloys of metal a, metal B and metal B. If several kilos of metal a are added, two parts of metal B and three parts of metal a will be added to the alloy. If the amount of metal A is doubled, three parts of metal B and seven parts of metal a will be added to the alloy. How much metal A is added for the first time? What is the percentage of metal a in the alloy

1: Unit price of shop a = 200 * (1 + 30%) = 260
Unit price of shop B = 200 * (1 + 20%) = 240
If store a sells x pieces, store B sells 2x
260X+8000=240*2X
The solution is X=

The purpose of calculating the difference between the maximum value and the minimum value of a group of data is to master the (d) A. number B. number of groups C. frequency D. range of change of this group of data

Select D

If for any non-zero rational number a and B, the new operation is defined as follows: a 0b = AB + 1, then what is the value of (- 5) ﹣ 0 (+ 4) ﹣ 0 (- 3)?

（-5） ○ （+4） ○ （-3）
=（-5×4+1） ○ （-3）
=-19 ○ （-3）
=（-19）×（-3）+1
=58

There are 140 fruit trees in the orchard. The ratio of apple trees to peach trees is 2:3, and that of peach trees to pear trees is 4:5. How many of these three kinds of trees are there?
This is not learned, please talk about XX

Peach tree: X; apple tree: (2 / 3) x; pear tree: (5 / 4) X
x+（2/3）x+（5/4）x=140 x=48
Peach tree: 48
Apple tree: 32
Pear tree: 60

If the algebraic formula x ^ 2 + 3x + 2 can be expressed as (x-1) ^ 2 + a (x + 1) + B, then the value of a + B is

Original formula = x ^ 2-2x + 1 + ax + A + B
=x^2-(2-a)x+(1+a+b)
2-a=-3 a=5
1+a+b=2 b=-4
Then a + B = 1