Given that one root of the equation x minus 2x minus C = 0 is 3, then the other root is 3

Given that one root of the equation x minus 2x minus C = 0 is 3, then the other root is 3

According to Weida's theorem, the sum of the two is the negative coefficient of the first term divided by the coefficient of the second term
So the other root is 2 / 1-3 = - 1

The root of equation 2x-1 / 1 + 3 = 2x-1 / X is

2x-1／1+3=2x-1／x
Multiply both sides of the equation by 2x-1 to get
1+3(2x-1)=x
1+6x-3=x
The solution is x = 2 / 5
Test: substitute x = 2 / 5 into the original equation, left = right
So x = 2 / 5 is the solution of the original equation

English translation
Section B

The most popular pet these days is big bellied pig. David Smith in South London has a big bellied pig named Connie. "Big bellied pig has become the best pet," David said. "She sits on the sofa with me every night watching TV. She is my best friend." of course, life with a pig is not perfect. "When

16. What is the least common multiple of 12 and 20?

16 12 20
Divide them all by four to get four, three and five
The least common multiple of 4 3 5 is 60
60 times 4 is 240

6: 42 = (x + 3): 80

Inner product = outer product
So
480=42x+126
42x=354
x=59/7

Given that a and B are rational numbers, try to compare the size of a + B and a-b

You can subtract by comparing the size of two numbers,
(a+b)-(a-b)=2b
So,
1, when ba-b;

There were 450 chickens and ducks in the feeding group. Later, half of the chickens were sold and 30 ducks were bought. At this time, the number of chickens was twice that of ducks. How many chickens and ducks were there?
You can't use the equation

If there are four chicken portions, half of them will be sold, and now there are two chicken portions
At this point, the chicken is twice as big as the duck, so
Duck for 1, the original duck: 1 - 30
therefore
4 parts + 1 part - 30 is 450
That is, 5 parts equals 450 + 30 = 480
1 portion = 480 △ 5 = 96 (piece)
Chicken: 96 × 4 = 384
Ducks: 450-384 = 66

Given that the maximum value of y = a-bcos x is 3 / 2 and the minimum value is - 1 / 2, we can find the maximum value, minimum value and period of y = - 4bsin ax

The maximum value is obviously a + | B | = 3 / 2
The minimum value is obviously a - | B | = - 1 / 2
A = 1 / 2,
Subtraction of two formulas: | B | = 1
The maximum value of y = - 4bsin (AX) is 4 | B | = 4
The minimum value is - 4 | B | = - 4
Period T = 2 π / a = 4 π

1. In △ ABC, if ∠ B + ∠ C = 2 ∠ a, ∠ B - ∠ C = 40 °, then ∠ a =? B =? C =?
2. ∠ 1 = ∠ 2, ∠ 3 = ∠ 4, ∠ BAC = 63 ° find ∠ DAC (the picture is published, it doesn't matter, the triangle is randomly divided into two halves, ∠ 1 and ∠ DAC are at the vertex)
3. There is a two digit number. The sum of its ten digit number and one digit number is 8. Find the qualified two digit number

1.∠A=60°,∠B=80° ∠C=40°
I don't know what you say, I can't understand
3. There are 8 double digits: 80, 71, 62, 53, 44, 35, 26, 17

1 2 3 5 8 13 in the future, we can deduce the general term formula of the sequence,

[（1＋√5）/2]^n /√5 － [（1－√5）/2]^n /√5