A math problem!!!! The headline catches the eye!! It s urgent!! Within 1 hour!! Give the process !!

It is easy to know that the angle c is equal to d, d is equal to the triangle abc is equal to 3 2 angle a, so the sum of angles a, c, abc is equal to 4 angle a, so 45°

(1) According to the title, it is known: b=24-a, and 1, (b-1 10b)+(a+1 6a)=24 or 2, (a-1 10a)+(b-1 10b)=24

Solution 1, get: a=9, b=15, solution 2, get: a=-12, because a can not be negative, so 2, round.

2) With the title, a=15, b=9, let: the height of the cylinder with a as the base radius is x, then the height of the cylinder with b as the bottom radius is 28-x.

And: x=(, solution: x=12, then the height of the cylinder with b as the base radius is 16 decimeters.

v (cylinder with a as the base radius) = r h = 15 12 = 2700 = 8100 cubic decimeters.

In the same way, the volume of another cylinder is: 1296 = 3888 cubic decimeters.

3) Because the ground radius of the vase with a as the bottom radius is 15 decimeters and the height is 12 decimeters, the most economical surface area of the material is: 15 15 2 + 15 12 4 = 1170 square decimeters.

In the same way, the other is: 9 9 2 9 16 4 = 738 square decimeters.

Let Xiaohong and Xiaoli each buy apples and particles with a mass of m, because the ratio of the mass of apples and pears bought by Xiaohong is 1:3, so the mass of the apples bought by Xiaohong accounts for 1 4 of the total mass, so the mass of apples is 1 4m, and the mass of particles is 3 4mThe same algorithm, because the mass ratio of apples and pears bought by Xiaoli is 2:

5, so Xiaoli buys apples with a mass of 2 7m and particles of 5 7m

Now add up the fruits of Xiaohong and Xiaoli to a total of 2m, and add the apples and apples together, which is 1 4m + 2 7m = 15 28m, which accounts for (15 28m) of the total mass 2m = 15 56, and the pears and particles are added together, accounting for 41 56 of the total mass, so apples are more than pears = 15:41

Convert the total number of apples and pears they bought into the same amount.

So, the ratio of apples to pears after mixing is: (7+8):(21+20)=15:41

Let the coefficient ratio of Xiaohong be k, then the pear has k, the apple has 3k, the coefficient ratio of Xiaoli is a, then the pear has 2a, the apple has 5a, and the mass is equal then there is 4k=7a, k=7 4a, and the mixed ratio is (k+2a) (3k+5a)=(15 4a) (41 4a)=15 41

It's so easy! Let the coefficient ratio of Xiaohong be k, then the pear has k, the apple has 3k, the coefficient ratio of Xiaoli is a, then the pear has 2a, the apple has 5a, and the mass is equal then there is 4k=7a, k=7 4a, and the mixed ratio is (k+2a) (3k+5a)=(15 4a) (41 4a)=15 41

Let the quality of the apples bought by Xiaohong be x, and the quality of the apples bought by Xiaoli be y

Red: x:3x; Xiaoli: 2y:5y, so 4x=7y

x+2y)/(3x+5y)=15/41

15:41 Red Z=x1+y1 Liz=x2+y2 x1=1 3y1 y1=3x1 x2=2 5y2 y2= 5 2x2 Bring in and out x1:x2=8:

7 yi:y2=20:21 assumes that the unit is 1

Add. Not necessarily. I haven't counted for a long time.

Set Xiaohong: Apple is 1x:3x than pear, Xiaoli 2y:5yThere is 4x=7y, and we get 1x+2y:3x+5y=15:49

Let the total mass of apples and pears be 1

Then the apple is 1 4 and the pear is 3 4

Xiaoli's is 2 7 5 7

Because the masses are equal, the specific gravity is reversed, and the answer is 1:3

I'm not sure if that's right.

Known: 1 2+1 5+1 8+1 11+1 20+1 41+1 110+1 1640=1

Both sides are subtracted by 1 2 at the same time

Get: 1 5+1 8+1 11+1 20+1 41+1 110+1 1640 1 2

0 (move 1 2 to the right of the equal sign, multiply by 1, and add 1 2 on both sides).

1/2+1/2-1/2-1/5-1/8-1/11-1/20-1/41-1/110-1/1640

0 hehe, I think so, it should be good,

The baby passes by, hehe, hehe, hehe.

Because AC=2 3, the angle AOC=180 degrees, there is a question about the angle AOB=120 degrees, and the angle BOC=60 degrees, so ao=OC=ob

3, so the length is 3 and the width is 3

Because it is a rectangle, the diagonal length is the same, and after drawing, you can know that the angle BOC + angle AOB = 180 degrees, so the angle AOB is 60 degrees, and it is easy to know that the triangle AOB is an equilateral triangle, so the side length of the rectangle AB=4, BC=

4 times root number 3.

Angular AOB = 2 angular BOC

Angular AOB + angular boc = 180

So the angle boc=60 and the angle aob=120

The triangle BOC is an equilateral triangle.

bc = oc = ac 2 = root number 3

ab=bc*tan60=3

Angle AOB = 2 angle BOC, angle AOC is a flat angle, i.e. 180 degrees, so angle AOB = 120 degrees.

The triangle AOC is an isosceles triangle (AO=BO), so the angle BAC=30 degrees In the right triangle ABC, the hypotenuse AC=2 root 3, then the right angle side BC=2 root 3 times sin30 degrees = root 3cm

The right-angled side ab = 2 roots 3 times cos30 degrees = 3cm In summary, the length of the rectangle is 3cm and the width is 3cm the root

1) If the root number is x+1, then x>=-1, if x, then x>=02) x is any real number, x 2 must be "=0

3) x>-2, note that x+2 is the denominator, and the denominator cannot be zero.

4) x>=0, the former root number needs to meet x>=0, the latter needs to meet x>=-1, and the synthesis can obtain x>=0

Because you don't know what items are included in the root number, in short, the root number should be non-negative, and then pay attention to the denominator can not be zero.

The number under the root number, i.e. the number to be opened, must be non-negative (at least at the middle and high school levels) and the denominator of the fraction is not equal to 0

So there is. x+1 0 is x -1

x +1 0 x can be any real number since x 0.

x+2 0 is x -2

x 0 and x+1 0 combine x 0

When you ask questions in the future, it's best to say that it's the first grade, the second year of junior high school?

I can't give you the answer, because your root number is incomplete, so I'll tell you how to do it:

1, let the formula below the root number be zero, calculate the result, then the meaningful are those values that are not zero, understand?

2, in the same way, let the denominator be 0, ditto, 3, if there is a root number in the denominator, combine 1,2 steps.

The arithmetic square root of 2x+1 is 2, so 2x+1=4

So x=

The root number is 2x+1=2, and 2x+1=4 after squared, so x=three-two.