Column equation solution application problem, is about chicken and rabbit with cage First, there are 40 chickens and rabbits, and 100 feet. How many chickens and rabbits are there

Column equation solution application problem, is about chicken and rabbit with cage First, there are 40 chickens and rabbits, and 100 feet. How many chickens and rabbits are there

Suppose there are x rabbits and (40-x) chickens
The equation is: 4x + 2 (40-x) = 100
2X+80=100
2X+80-80=100-80
2X=20
2X divided by 2 = 20 divided by 2
X=10
Chicken: 40-10 = 30

Huahui TV factory produced 4000 LCD color TV sets in September, and the output in October was 200 more than twice that in September. How many LCD color TV sets were produced in October?

4000x2 + 200 = 8200 (set)
A: 8200 LCD color TV sets were produced in October

2. The circumference of a rectangle is 648 meters, and its length is twice the width. How many meters is its length?
(please write down the solution, for example: let the width be x meters and the length be 2x meters.)
2. The circumference of a rectangle is 648 meters, and its length is twice the width. How many meters is its length?
(please write the solution, for example: let the width of the solution be x and the length be 2x meters.)

If its width is x meters, its length is 2x meters
2（x+2x）=648
We get x = 108
2x=216
Therefore, it is 216 meters long
(remember to give points ~)