Solving the application problem of binary linear equation There is only one car for a class to go for an outing in Beishan Mountain 18 kilometers away, which is divided into two groups. Group A takes the car first, group B walks, and the car goes to A. group A gets off the car and walks, and the car returns to group B. the last two groups arrive at Beishan Mountain at the same time. The known speed of the car is 60 km / h, and the walking speed is 4 km / h? Please set two unknowns

Set the distance between point a and Beishan station as X,
The distance between the car and group B is (18-2x) km,
A walking time x / 4
Driving time after leaving a car [x + 2 (18-2x)] / 60
X/4=[X+2(18-2X)]/60;
4X+144-16X=60X;
72X=144;
X = 2 (km)
A: the distance from point a to Beishan station is 2km

Help solve a binary linear equation application problem
Zhang Ming deposits 2000 yuan into the bank on a fixed term basis, withdraws 1000 yuan after maturity, and deposits the remaining 1000 yuan and interest into the bank on a fixed term basis. After maturity, he obtains a total of 1091.8 yuan of principal and interest. He seeks the annual profit of one year's fixed deposit

The annual interest rate of a year's fixed deposit is X
[2000*(1+X)-1000]*(1+X)=1091.8
X=

Solving practical problems with quadratic equation of two variables
Part of the information of domestic water is as follows: the part within 5M3 (including 5M3) is 2 yuan / m3, and the part above 5M3 is x yuan / m3. It is known that xiaojingjia and Xiaolei paid 19 yuan and 31 yuan respectively in May, and Xiaolei's water consumption is 1.5 (1.5) times of xiaojingjia's
Use binary linear equations!

It should be: Xiaoshu's water consumption is 1.5 times that of Xiaolu's
First calculate the amount of money for two families with 5 cubic meters, 5 × 2 = 10 yuan
The two families take out 5 cubic meters of water (the remaining money per cubic meter of water is equal)
19-10 = 9 yuan
31-10 = 21 yuan
According to the water consumption of xiaoshujia is 1.5 times of that of xiaolujia, the equation is listed
(9÷X+5) ×1.5=21÷X+5
Can the equation be solved!
The value of X is x = 3

If 2x ^ NY ^ 4 and 1 / 2m ^ 2x ^ 2Y ^ (the absolute value of m-n) are both binomials of degree six about X and y, and the coefficients are equal, the value of M and N can be obtained

If 2x ^ NY ^ 4 and m ^ 2x ^ 2Y ^ (the absolute value of m-n) are both binomials of degree six about X and y, and the coefficients are equal
Then 2 = ½ m ^ 2, N + 4 = 2 + | M-N | = 6
So m = - 2, n = 2
If you don't understand, I wish you a happy study!

Cut a sector with a central angle of 45 ° from a circular sheet of iron with a radius of 8 cm. Use this sector sheet of iron to make a cone. Its volume is 3.14 cubic cm. Calculate the height of the cone

Cut a sector with 45 ° central angle from a circular sheet iron with a radius of 8 cm, and make a cone with this sector iron sheet, then the bus length of the cone is 8 cm, the circumference of the bottom surface of the cone is 2 * 3.14 * 8 * 45 ° / 360 ° = 6.28 cm, the radius of the bottom surface of the cone is 6.28 / (2 * 3.14) = 1 cm, so the cone height h = √ (8 & sup2; - 1 & sup2;) = √ 63 = 3

How to calculate the equation x 10 7 2 35

x+7=35
x=35-7
x=28
test
28+7=35
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Nonnegative real numbers x1, X2, satisfying X1 + x2 = √ lower 1-x1 - x2 + 1

Square on the left = 1-x1-x2 + 1 + 2 √ [(1-x1) * (1-x2)] > = 1-x1-x2 + 1
Square on the right = 1-x1-x2 + 1
Get the square on the left > = the square on the right
And because the left side, the right side > = 0
So left > right
PS: is it possible to remove ambiguity by using parentheses when typing, or who knows where your parentheses work

The radius of the big circle is equal to the diameter of the small circle, and the circumference ratio of the big circle to the small circle is What is the area ratio of the big circle to the small circle A.2：1 B.1：2 C.1：4 D.4：1．

Let the radius of the small circle be r, then the diameter of the small circle be 2R, and the radius of the large circle be 2R, then: (1) [2 × π× (2R)]: (2 π R), = 4 π R: 2 π R, = 2:1; (2) π (2R) 2: π R2, = 4 π R2: π R2, = 4:1; answer: the ratio of the circumference of the large circle to the circumference of the small circle is 2:1, and the ratio of the surface product of the large circle to the area of the small circle is 4:1

Divide a by 3 / 5 = B by 1 / 3 = C by 1 / 4 = D by 8 / 7, and arrange ABCD from large to small in order

Think of their number as equal to one, so the result is a = five-thirds, B = 3, C = 4, d = eight seventh, so c > b > a > D

The relationship between the root and coefficient of one variable polynomial
In higher algebra, what is the relationship between the root of a polynomial of degree n of one variable and its coefficient

This is the Veda theorem
In general, for an equation of degree n with one variable ∑ AIX ^ i = 0, its roots are denoted as x1, X2 We have ∑ xi = (- 1) ^ 1 * a (n-1) / a (n) ∑ xixj = (- 1) ^ 2 * a (n-2) / a (n) Π xi = (- 1) ^ n * a (0) / a (n), where ∑ is sum and Π is product