Calculation question: 2A (a + b) - (a + b) ^ 2

Calculation question: 2A (a + b) - (a + b) ^ 2

2a(a+b)-(a+b)^2
=2a^2+2ab-a^2-2ab-b^2
=a^2-b^2

There are two points a and B on the known line segment a
It is known that there are two points a and B on the line a, and ab = 12cm, point C is also on the line a, and the distance from point B is 4cm, D is the key point of AC, e is the midpoint of BC, find the length of line de. if it is good, add points
Can you write the process for me?

Because CB = 4cm, ab = 12cm
So AC = ab-cb
=12-4
=8cm
Because D is the midpoint of AC, AC = 8cm
So DC = 1 / 2Ac
=1/2×8
=4cm
And because e is the midpoint of CB, BC = 4cm
So CE = 1 / 2BC
=1/2×4
=2cm
So de = DC + De
=4+2
=6cm

(passenger cars from city a to city B, regulations.)
For buses from city a to city B, it is stipulated that each passenger can carry a certain amount of luggage free of charge, and the excess part will be charged according to the quality. When a, B, and C take a bus from city a to city B, both a and B have no luggage, but C has 150 kg of luggage. Except for the part that C can carry free of charge, they need to pay 8 yuan, It's only 4 yuan. How many kilos of luggage can each person carry free?

Suppose that each person can carry luggage for free x kg 8 / (150-x) = 4 (150-3x), then x = 25 kg~~
Thank you!

If the sum of five consecutive even numbers is 320, the smallest of the five even numbers is 320______ ．

If the sum of five consecutive even numbers is 320, then: the third even number of the five consecutive even numbers (that is, the middle one) is 320 △ 5 = 64. That is to say, the five numbers are 60, 62, 64, 66 and 68. Therefore, the smallest even number is 60. So the answer is: 60

The sum of two consecutive even numbers is 10, and the two numbers are () and () and the sum of them is 10
The sum of two consecutive even numbers is 10. These two numbers are () and (). The largest even decomposition prime factor is ()

4 6

How many different even numbers of four digits can you write with 3.0.0.2
Use each number at least once

3002
three thousand and twenty
three thousand and two hundred
two thousand and thirty
two thousand and three hundred
Because the requirement is even, the last digit must be even and can only be 0 or 2, and 0 cannot be the first digit, so the first digit can only be 2 or 3

With four numbers of 0, 1, 2 and 3, you can form () different even numbers

48

There are three continuous natural numbers, the smallest one is a, then the largest one is a______ ．

The biggest one is: a + 1 + 1 = a + 2. A: the biggest one is a + 2. So the answer is: a + 2

Three consecutive even numbers. If the largest number is a, then the smallest number is a

a a-2 a-4
A: the minimum number is A-4

The sum of three consecutive even numbers is 108, and these three numbers are () () ()

34、36、38