When m = (), the parabola y = xsquare - 2x + m has two intersections with the coordinate axis

When m = (), the parabola y = xsquare - 2x + m has two intersections with the coordinate axis

y = x² - 2x + m = (x-1)² + m - 1
The axis of symmetry is: x = 1
The minimum value is: m - 1
When m = 1, the parabola has an intersection with the x-axis and the y-axis

Find the distance between the coordinates of the two intersections of the straight line X-Y + 2 = 0 and the square of X + y = 25

x-y+2=0
x=y-2
Square of X + square of y = 25
(y-2)^2+y^2=25
2y^2-4y+4=25
2y^2-4y-21=0
Discriminant = 16 + 21 * 8 = 184
Y1 = (4 + 2 radical 46) / 4 = (2 + radical 46) / 2
Y2 = (2-radical 46) / 2
The coordinates of the intersection [(radical 46-2) / 2, (2 + radical 46) / 2], [(- 2-radical 46) / 2, (2-radical 46) / 2]
The distance between them = root (x1-x2) ^ 2 + (y1-y2) ^ 2
=Root 46

In a rectangular ABCD, (with ab as the width) AB = 2, BC = 4, rotating around AB, what is the volume?

Equivalent to the volume of cylinder with base radius = BC = 4, height = AB = 2: π × 4 × 4 × 2 = 32 π

If the power 0 of (2x-1) is 1, then the value range of X is?

0 power of (2x-1) = 1,
2x-1≠0
x≠1/2

A taxi company has 100 taxis, and the average daily gasoline cost of each taxi is 80 yuan. In order to reduce environmental pollution, the market introduces a device called "CNG" to convert gasoline to natural gas, and the price of each taxi is 4000 yuan. After the company refits some vehicles for the first time, it calculates that the daily fuel cost of the refitted vehicles accounts for the daily fuel cost of the remaining unmodified vehicles Q: (1) how many taxis has the company refitted? How much is the average daily fuel cost of each taxi after modification lower than that before modification? (2) If the company refits all taxis at one time, how many days can it recover the cost from the saved fuel cost?

(1) Suppose the company refits y taxis for the first time, and the fuel cost of each taxi after refitting is reduced by a percentage of X. according to the meaning of the problem, the equations are as follows: 80 (1 − x) y = 320 × 80 (100 − y) 2Y × 80 (1 − x) = 25 × 80 (100 − 2Y). The solution is x = 25 = 40%, y = 20 The daily fuel cost of the car is 40% lower than that before modification; (2) if the cost can be recovered in M days after one-time modification, then 100 × 80 × 40% × M = 4000 × 100, so m = 125 (days) a: if the company refits all taxis at one time, the cost can be recovered from the saved fuel cost in 125 days

Given the angle man = 120 degrees, AC bisector angle man, angle ABC + angle ADC = 180 degrees, verify whether AB + ad is equal to AC

On DM, cut off de = AB, connect EC through C, make CF perpendicular to am through F, make CP perpendicular to an through P, because ∠ ADC + ∠ ABC = 180 °∠ ADC + ∠ EDC = 180 °∠ EDC = ∠ ABC AC bisector angle man, so CF = CP ∠ CFD = ∠ CPB = 90 ° so triangle CFD is equal to triangle CPB CD = CB triangle Dec is equal to triangle BAC ∠ CED = ∠ cab = angle CEA = 60 ° so triangle EAC is equilateral triangle So AC = AE = AD + de = ad = ab

It takes 40 hours for one person to do a job. Now it is planned that two people will do it for 4 hours first, and the rest of the work will be completed in 8 hours. How many more people are needed? (assuming everyone's efficiency is the same)

Suppose X more people are needed, then according to the meaning of the question: 140 × 2 × 4 + (x + 2) 40 × 8 = 1, the solution is x = 2

There are 41 students in class 1, Grade 7. All of them take part in soil transportation. The head teacher takes 30 shoulder poles and distributes them to the students. He arranges the boys to carry the soil and the girls to carry the soil. Xiaoming is surprised to find that the shoulder poles brought by the head teacher are not many, but they just run out. Do you know how many boys and how many girls there are in class 1, Grade 7

If there are x boys, there are (41-x) girls
One man carries the earth with one shoulder pole, and two men carry the earth with one shoulder pole
Boys use a total of X poles, girls use a total of (41-x) / 2 poles
According to the meaning of the question, the equation can be listed as follows: x + (41-x) / 2 = 30
If x = 19, then 41-x = 22
A: there are 19 boys and 22 girls in class 1, Grade 7

The area of a rectangle is 1225 square centimeters as that of a square. The area of a circle is 1256 square centimeters. Find their circumference
To calculate and show

(1) Rectangle: if the length is a and the width is B, then a * b = 1225, that is, B = 1225 / A, and the circumference is:
L = 2 * (a + b) = a + 1225 / A
(2) Square: if the side length is a, then a ^ 2 = 1225, that is, a = 35, then the perimeter is L = a * 4 = 35 * 4 = 140
(3) Circle: let radius be r, π * R ^ 2 = 1256, then r = √ (1256 / π) = 2 √ (314 / π)
Perimeter: S = 2 * π * r = 2 * π * 2 √ (314 / π) = 4 √ (314 π)

If rational numbers a and B satisfy | ab-2 | + | 1-B | = 0, try to find 1 / AB + 1 / (a + 1) (a + 1) + 1 / (a + 2) (a + 2) +... + 1 / (a + 2004) (B + 2004)
value

Because | ab-2 | + | 1-B | = 0
So | ab-2 | = 0, | 1-B | = 0
So ab-2 = 0, 1-B = 0
So B = 1, a = 2
The following. Are you sure it's right?