50 points A few math problems, a few math problems 50 points

Question 2: If Xiao Ming wants to go out, the luggage he brings is 40cm long, 30cm wide and 60cm high, can a 70cm long umbrella be loaded with Li Xiang?

Root number (40 2 + 30 2 + 60 2) = root number 6100>70 so I can carry luggage.

Question: Given that the angle of the RT triangle ABC is C=90 degrees, if A+B=7CM and C=5CM, what is the area of the RT triangle ABC?

a = 3, b = 4, area of 6

Question 3: What is the square root of a number that is a+3 and 2a-15?

a+3)^2=(2a-15)^2

a^2+9+6a=4a^2+225-66aa^+72-22a=0

a = 4 or a = 18

When a=4.

a+3=7,2a-15=-7 (rounded).

When a=18.

a+3=21,2a-15=21

So the number is 21

Question 4: A rectangle, if the length is reduced by 6 meters, the width is increased by 3 meters, and the area remains the same. If the length is increased by 3 meters and the width is decreased by 3 meters, and the area remains the same, what is the area of this rectangle?

Let the length be a and the width be b

a-6)(b+3)=ab

a+3)(b-3)=ab

Decompose, got. ab-6b+3a-18=ab

ab+3b-3a-9=ab

The solution yields a=-12

b = -9 area ab = 108

I've pretty much figured it out

Points should be given to me

Oh haha

1.[x + root number (square of x + 2002)]*y + root number (square of y + 2002)] = 2002, find the value of x squared - 3xy-4*y squared - 6x-6y + 58.

2.ABCD is known to be rectangular, and A and B start from A and B at the same time and move in the counterclockwise direction of the rectangle, i.e., A-B-C-D-A-B....It is known that the speed of A is 65 meters and the speed of B is 74 meters

B can catch up with A by running at least a few laps; How many laps does B run to catch up with A?

A1[x + root number (square of x + 2002)]*y + root number (square of y + 2002)] = 2002, find the value of x squared - 3xy-4*y squared - 6x-6y + 58.

Solution: The value sought is 58. The process is as follows:

Multiply on both sides of the known equation by [x-root(x2+2002)]*y-root(y2+2002)], and arrange it.

x 2-(x 2+2002)][y 2-(y 2+2002)]=2002*[x-root(x 2+2002)]*y-root(y 2+2002)]], simplified to x-root(x 2+2002)]*y-root(y 2+2002)]=2002, so the above equation is equal to the known equation, and the two are separated.

xy-x root number (y 2 + 2002) - y root number (x 2 + 2002) + root number (x 2 + 2002) * root number (y 2 + 2002) = xy + x root number (y 2 + 2002) + root number (x 2 + 2002) * root number (y 2 + 2002), so as to obtain x root number (y 2 + 2002) = -y root number (x 2 + 2002), 1).

Both sides are squared.

x 2 = y 2, that is, x = plus or minus y, if x = y, by (1), x=y=0, then the desired formula = 58;

If x=-y, substituting the desire, the result is also 58.

So the value sought is 58.

Yes. I figured it out. 1.No solution.

The square of the diagonal = the square of the length + the square of the width + the square of the height. The diagonal is about 78, so put it. Under.

a+3）^2=（2a-15)^2

Multiply the ten sons to get a1 = 18 a2 = 4

Set the side length a, b

a-6)(b+3)=ab

a+3)(b-3)=ab

Calculate a=-12

b=-9There is a problem with the question... The score belongs to me haha, it's funny, it seems that I have found a lot of people for my life. . .

1. Solution: Let the radius of the bottom circle of the cylinder be r, then the height of the cylinder is 2r, and the edge length of the cube is 2r, there is an equation:

r3=628÷

r3=100

The volume of the cube is equal to: 2r 2r 2r = 8 r3 = 8 100 = 800 (cubic centimeters).

A: The volume of the cube is 800 cubic centimeters.

2. The largest cylinder is the inscribed circle on the upper surface of the cube, so the diameter is 8, that is, the radius is 4. The height is still the height of the cube.

So for: 4 2*

3, cubic centimeters.

4. The oil drum is filled with oil is liters.

And 1 liter = 1 cubic decimeter = 1000 cubic centimeters.

So the volume of the oil drum is cubic centimeters.

So the height of the oil drum = the volume of the bottom area.

When picked. Radius = 10cm

Base area = square centimeters.

So height = 7850 314 = 25 cm.

5. The original bucket can hold 20 kg of water.

(1) Let the radius of the bottom surface be r, then, volume = r 3 = 100 (2) 4 2 * 8 = 128

5） 40/2=20kg

Cubic centimetre; 2. cubic decimeters; 3. Square centimeter cm kg

The first number: 100

Second number: 75

The third number: (100+75) 2=

Fourth number: (100+75+=(=.)

Fifth number: (100+75+=(=.)

And so on, the 2008th number is:

The integer part of the 2008th number is: 87

Can I score points?

The 2008th number is, I programmed it, but it's certainly not 1

The following numbers are all so the integer part is 87Try it if you don't believe it. 2008 bit is also 87

4 7-36 * 2 3 = 56 and 4 7

3.The latter term = (15 + 3) * 2 3 = 12

12-2=10 should be added

4.Efficiency ratio = 1 1 4:1 1 3 = 4:35A efficiency = 1 20 B efficiency = 1 3 5 = 1 15 two people working = 1 (1 20 + 1 15) = 60 7 days.

6.Interest = 500 * RMB.

7.B alone = 1 (1 15-1 20) = 60 days.

There are 3 ways to place the position, the first one is placed in 1 row, the second is placed in 2 rows, and the third is placed in 3 rows.

You don't have to do a single roll.

The back waves of the Yangtze River push the front waves, and the new generation of young people is awesome!!