How to solve the equation of (40-x) + X + (36-x) + 6 + 12 + 4 + 16 = 100, please explain each step,

How to solve the equation of (40-x) + X + (36-x) + 6 + 12 + 4 + 16 = 100, please explain each step,

（40-x）+x+(36-x)+6+12+4+16=100 40-x+x+36-x+6+12+4+16=100 40+36-x+6+12+4+16=100 114-x=100 114-100=x x=14

1. 0.4: x = (1 + 1 / 7): 5 2, 0.8: 3 and 3 / 4 = (5-x): 0.75
3. X: 3 / 4 = 12:1 / 8 solve the equation, write the process, please write clearly

1、 0.4：x=（1+1/7）：5
The product of the outer term is equal to the product of the inner term,
∴（8/7）x=2,
∴x=7/4.
2. 8:3 and 3 / 4 = (5-x): 0.75
(15 / 4) (5-x) = 0.6,
75-15x=2.4,
72.6=15x,
x=4.84.
3.x：3/4=12：1/8
x/8=9,
x=72.

How to solve the equation 2 (| x + 1 | - 2) - 3 (2 | x + 1 | - 1) = 7 (1 | x + 1 |) - 2?

Exchange, y = | x + 1|
The original equation is reduced to 2y-4-6y + 3 = 7-7y-2
That is, 3Y = 6, y = 2
So x = 1 or - 3

Take the sector with the center angle of 120 ° and the area of 3 π as the side of the cone. Calculate the surface area and volume of the cone
Please master advice, put forward the formula to be used,

According to 3 π = π R ^ 2 * (120 / 360) R ^ 2 = 9 r = 3 arc length = (2 / 3) π r = (2 / 3) π * 3 = 2 π bottom area = (2 π / 2 π) ^ 2 * π = π surface area = 4 π bottom radius = 1, cone height = root 8

Three mathematical problems
1. When they meet, a travels 10.5 kilometers more than B. one tenth of the distance a travels is equal to one third of the distance b travels. How many kilometers are there between East and West?
2. A and B are facing each other from a and B at the same time. When they meet, they are 50 meters away from A. after meeting, they continue to move forward, return to their destination immediately, and meet again 40 meters away from A. what is the distance between a and B?
3. When they meet, the distance ratio of a and B is 5 to 7. After meeting, a continues to drive at the original speed of 33.6 kilometers per hour, and it takes another 6 hours to arrive at B. how long is the meeting time of a and B?
To calculate, please

1. The distance between East and West is x km,
From: 1 / 10 of a's travel = 1 / 3 of B's travel
The ratio of a to B is 10:3
Formula: X (10 / 13-3 / 13) = 10.5
The solution is: x = 19.5

Inequality 3x / x2-1

1-3x/(x²-1)>=0
(x²-3x-1)/(x²-1)>=0
That is, (X & # 178; - 3x-1) (X & # 178; - 1) > = 0
The zeros are - 1, (3 - √ 13) / 2,1, (3 + √ 13) / 2
The denominator is not equal to 0
therefore
x

As shown in the figure, the area of the circle is 25.12 square centimeters, and the area of the shadow part is______ Square centimeter

Because the area of the circle = π R2, R2 = 25.12 △ 3.14 = 8 (square centimeter); answer: the area of the shadow is 8 square centimeter; so the answer is: 8

Let a (1, - 2,11) B (6, - 1,4) C (4,2,3) d (12,7. - 12) prove that ABCD is coplanar

c-a=(3,4,-8)
d-b=(6,8,-16)=2*(3,4,-8)
Then AC is parallel to BD
∴
ABCD coplanar

What is the minus half power of 2?

Calculation formula of arc length

Arc length = center angle of arc (unit: radian) * arc radius