It is known that one root of the equation x-2x + k = 0 about X is 3. Find the value of K and another real root of the equation

It is known that one root of the equation x-2x + k = 0 about X is 3. Find the value of K and another real root of the equation

I don't want to tell you the answer directly. I want to remind you that because 3 is a root of X, you can enter the formula instead of 3, find out the value of K, and then solve the equation

Why is goodness of fit equal to the square of correlation coefficient in univariate linear regression

I am a sophomore in senior high school, and I also found this conclusion. But I asked the teacher, she said that there is a relationship between the two, but it is not a simple square relationship. There is a relationship between the two in the teaching reference, which is very complex. You can have a look at it

How do you calculate the volume and area of the ellipse?
It is known that the major axis is 2.45m, the minor axis is 1.9m and the height is 1.9m
What is the volume and area of this ellipse?

The upper surface area s = 1.9 × 2.45 × π = 4.655 π
Volume v = sh = 4.655 π × 1.9 = 8.8435 π

Shanghai nine year compulsory Edition Grade 6 Volume 1 mathematics exercise book page 58 question 6 (3) and page 59 question 10
5 points for one question and 15 points for two questions

Page 58: 360 / 180 × 3.14 × 8 × 8 = 100.48 CM & sup2;
100.48-8×8=36.48㎝²
Page 59: 360 / 300 × 12 × 12 × π = 120 π M2
120π+3π×2≈396㎡

Let X and y be the two real roots of the equation m2-2am + A + 6 = 0, then the minimum value of (x-1) 2 + (Y-1) 2 is ()
A. -1214B. 18C. 8D. 34

Then (x-1) 2 + (Y-1) 2 = x2 + y2-2 (x + y) + 2 = (x + y) 2-2xy-2 (x + y) + 2 = (2a) 2-2 (a + 6) - 4A + 2 = 4a2-6a-10 = 4 (a-34) 2-494

People's education press fifth grade volume I mathematics final test questions
1、 Fill in the blanks
1. Xiaoling bought four pens, each a yuan, and five exercise books, each B yuan. The total cost is () yuan. When a = 0.5, B = 1.2, the total cost is () yuan
2. Xiaoqiang has a cold recently. The doctor requires him to drink no less than 2000 ml of water every day. His water cup can hold 250 ml of water at most, so he should drink at least () glasses of water a day
3. A two decimal place is reserved. One decimal place is 3.0. The maximum number of the two decimal places is ()
4. When the number is 100 times the original number, it is 64, which is ()
5. A chair costs n yuan, a table costs 6 times as much as a chair, and a set of tables and chairs costs () yuan
6. The area of a parallelogram is 32 square centimeters, its bottom is 4 centimeters, its height is () centimeters, and the area of a triangle equal to its height is () square centimeters
2、 I'm the best judge of right and wrong!
1. Divide a number by a decimal. The quotient may be a decimal
2. The equation must be an equation
3. If a number is multiplied by 0.8, the product is smaller than the original number
4. The area of a triangle is half that of a parallelogram
5. The quotient of a decimal divided by a decimal must be a decimal
6. The median and mean of a set of data may be equal
3、 Easy choice
1. 795 to two decimal places is ()
A、0.79 B、0.80 C、0.8
2. The following () is the equation
A、x+3 B、x+3=7 C、x+9
3. If you look at a cuboid in one place, you can see its () at most at one time
A. One face B, two faces C, three faces
4. A triangle and a parallelogram have the same area and the same base. The height of a triangle is 1.6 decimeters, and the height of a parallelogram is () decimeters
A、1.6 B、3.2 C、0.8
4、 Calculation
1. Write the number directly
2.5x2= 0.24/0.3= 0.108/0.01= 7.1-1.7=
6.18/0.6= 0.12+0.8= 0.2x500= 1.4x0.5=
0.6/3= 0.4x0.5= 8.1/0.81= 1.4/0.4=
2. Calculate the following questions
60-2.3x12 50x(0.8+0.4) 8.88x9+8x1.11
3.05/0.25/4 4.27/0.7x1.3 18.9-18.9/1.4
3. Solve the equation
5x-7.8=20.2 2.5x-x=1.8 4x+8x=120
A food factory produces 1645 bags of Yuanxiao in a week, each 18 bags is packed in a box. How many such cartons are needed to complete these Yuanxiao?
2. My mother went to the mall to buy 3 boxes of toothpaste and 2 bags of washing powder. It cost 30.8 yuan in total. A bag of washing powder costs 6.7 yuan. How much is a box of toothpaste?
3. The perimeter of a square flower bed is 4.8 meters. How many square centimeters is the area of this flower bed?
4. Grandfather is 75 years old, five years older than Xiao Ming's age. How old is Xiao Ming
Who makes all the best for whom

1. Xiaoling bought four pens, each a yuan, and five exercise books, each B yuan. The total cost is (4a + 5b) yuan. When a = 0.5, B = 1.2, the total cost is (8) yuan
2. Xiaoqiang has a cold recently. The doctor requires him to drink no less than 2000 ml of water every day. His water cup can hold 250 ml of water at most, so he should drink at least (8) glasses of water a day
3. A two place decimal is reserved. One place decimal is 3.0. The maximum number of this two place decimal is (3.04). (is it rounded? It's not 3.09)
4. When a number is 100 times the original number, it is 64, which is (0.64)
5. A chair costs n yuan, a table costs 6 times as much as a chair, and a set of tables and chairs costs (7n yuan)
6. The area of a parallelogram is 32 square centimeters, its bottom is 4 centimeters, its height is (8) centimeters, and the area of a triangle equal to its height is (16) square centimeters
2、 I'm the best judge of right and wrong!
1. If a number is divided by a decimal, the quotient may be a decimal
2. The equation must be an equation
3. If a number is multiplied by 0.8, the product is smaller than the original number
4. The area of a triangle is half that of a parallelogram
5. The quotient of a decimal divided by a decimal must be a decimal
6. The median and mean of a set of data may be equal
3、 Easy choice
1. 795 to two decimal places is (b)
A、0.79 B、0.80 C、0.8
2. The following (b) is the equation
A、x+3 B、x+3=7 C、x+9
3. Observe a cuboid in one place, and you can see its (c) at most at one time
A. One face B, two faces C, three faces
4. A triangle and a parallelogram have the same area and the same base. The height of a triangle is 1.6 decimeters, and the height of a parallelogram is (c) decimeters
A、1.6 B、3.2 C、0.8
4、 Calculation
1. Write the number directly
2.5x2=5 0.24/0.3=0.8 0.108/0.01= 10.8 7.1-1.7=5.4
6.18/0.6=10.3 0.12+0.8=0.92 0.2x500=100 1.4x0.5=0.7
0.6/3=0.2 0.4x0.5=0.2 8.1/0.81=10 1.4/0.4=3.5
2. Calculate the following questions
60-2.3x12 50x(0.8+0.4) 8.88x9+8x1.11
=60-27.6 =50x1.2 =79.92+8.88
=32.4 = 60 = 88.8
3.05/0.25/4 4.27/0.7x1.3 18.9-18.9/1.4
=3.05/（0.25x4）=6.1x1.3 =18.9-13.5
=3.05/1 =7.93 =5.4
=3.05
3. Solve the equation
5x-7.8=20.2 2.5x-x=1.8 4x+8x=120
5x=20.2+7.8 1.5x=1.8 12x=120
5x=28 x=1.2 x=10
x=5.6
5、 Solve the problem
A food factory produces 1645 bags of Yuanxiao in a week, each 18 bags is packed in a box. How many such cartons are needed to complete these Yuanxiao?
1645 / 18 ≈ 91 (pieces) 91 + 1 = 92 (pieces)
A: it takes 92 such cartons to complete the Lantern Festival
2. My mother went to the mall to buy 3 boxes of toothpaste and 2 bags of washing powder. It cost 30.8 yuan in total. A bag of washing powder costs 6.7 yuan. How much is a box of toothpaste?
Set a box of toothpaste X Yuan
3x+2x6.7=30.8
3x+13.4=30.8
3x=30.8-13.4
3x=17.4
x=5.8
A: a box of toothpaste costs 5.8 yuan
3. The perimeter of a square flower bed is 4.8 meters. How many square centimeters is the area of this flower bed?
4.8 / 4 = 1.2 (m) 1.2x1.2 = 1.44 (cm2)
A: the area of this flower bed is 1.44 square centimeter
4. Grandfather is 75 years old, five years older than Xiao Ming's age. How old is Xiao Ming
Let Xiao Ming be x years old this year
5x+5=75
5x=75-5
5x=70
x=16
A: Xiao Ming is 16 years old
There may be mistakes, but I tried my best

Given that circle C1: x + y + 2x + 3Y + 1 = 0, circle C2: x + y + 4x + 3Y + 2 = 0, judge the position relationship between circle C1 and circle C2. Thank you,

Circle C1 is reduced to: (x + 1) + (y + 3 / 2) = 9 / 4, center coordinate R1 is: (- 1, - 3 / 2), radius is 3 / 2, circle C1 is reduced to: (x + 2) + (y + 3 / 2) = 17 / 4, center coordinate R2 is: (- 2, - 3 / 2), radius is √ 17 / 2. In order to know the position relationship between circle C1 and circle C2, we must find the distance between R1 and R2

Fourth grade volume I oral arithmetic card answers

I don't know, but you can search Baidu Library for praise

If the side length of a square is increased by 6 meters, the area will be increased by 96 square meters
I want the process that I can understand. Thank you

(x + 6) square - x square = 96
x＝5
So the original square area X square = 25

When is the acceleration of simple harmonic motion negative and positive

According to the decrease of velocity, we can only judge whether the acceleration is negative (relative to the direction of velocity), but not how the acceleration (absolute value) changes. Just like decelerating motion, as long as the velocity is positive, the displacement always increases. Simple harmonic vibration