Set chicken x and rabbit 8-X.

2x+4(8-x)=20

2x+32-4x=20

2x= 12

x=6

Six chickens and two rabbits.

2. Chickens and rabbits live in the same cage, 1 1 head, 36 legs. How many chickens and rabbits are there?

Set chicken x and rabbit11-x.

2x+4( 1 1-x)=36

2x+44-4x=36

2x=8

x=4

Four chickens and seven rabbits.

3. There are chickens and rabbits in the cage, ***5, 14 legs. How many chickens and rabbits are there?

Set chicken x and rabbit 5-X.

2x+4(5-x)= 14

2x+20-4x= 14

2x=6

x=3

Three chickens and two rabbits.

4. Uncle Wang bought 120 yuan 1kg black tea and 160 yuan 1kg green tea, * * * 14 kg, and * * spent 2080 yuan. What kind of tea is he drinking? How many kilograms did Ge Ye buy?

Set black tea x and green tea14-x.

120 x+ 160( 14-x)= 2080

120 x+2240- 160 x = 2080

40x= 160

x=4

4kg black tea and 10 kg green tea, 5. Practice.

1. There are x chickens and 8-X rabbits.

2X+4(8-X)=20

2X+32-4X=20

2X= 12

X=6

Six chickens and two rabbits.

2. Set X chickens and 1 1-X rabbits.

2X+4( 1 1-X)=36

2X+44-4X=36

2X=8

X=4

Four chickens and seven rabbits.

3. Set up X chickens and 5-X rabbits.

2X+4(5-X)= 14，2， 1。 There are x chickens and 8-X rabbits.

2X+4(8-X)=20

2X+32-4X=20

2X= 12

X=6

Six chickens and two rabbits.

2. Set X chickens and 1 1-X rabbits.

2X+4( 1 1-X)=36

2X+44-4X=36

2X=8

X=4

Four chickens and seven rabbits.

3. Set up X chickens and 5-X rabbits.

2X+4(5-X)= 14

2X+20 ..., 2, 1, x chickens, 2X+4(8-X)=20.

2. Set X chickens, 2X+4( 1 1-X)=36.

3. There are X chickens, 2X+4(5-X)= 14.

4. Let black tea be x kg,120 x+160 (14-x) = 2080,2, and the following questions are all set for X rabbit.

1 Question: 2(8-X)+4X=20

Question 2: 2( 1 1-X)+4X=36.

Question 3: 2(5-x)+4x= 14

Question 4: Buy black tea xkg. 120 x+ 160( 14-x)= 2080，2， 1。 Chickens and rabbits live in the same cage, with 8 heads and 20 legs. How many chickens and rabbits are there?

With x chickens, there are (8-x) rabbits.

2x+4(8-x)=20

2x+32-4x=20

(chicken) x=6

(Duck) 8-6=2

A: There are 6 chickens and 2 rabbits.

2. Chickens and rabbits live in the same cage, 1 1 head, 36 legs. How many chickens and rabbits are there?

There are x chickens, and there are (1 1-x) rabbits.

2x+4( 1 1-x)=36

2,2, 1, 2 times 8= 16 (strips), 20- 16=4 (strips), 4-2=2 (strips), rabbit: 4 divided by 2=2 (chickens only): 8-2=6.

2,2 times 1 1=22 (strips), 36-22= 14 (strips), 4-2=2 (strips), rabbit: 14 divided by 2=7 (chickens only):/kloc.

3, 2 times 5= 10 (strips), 14- 10=4 (strips), 4-2=2 (strips), rabbit: 4 divided by 2=2 (only), 5-2=3 (only).

4. 14 times 120= 1680 (yuan), 2080- 1 ..., 2 1 chicken 6 rabbit 2.

2 Chicken 4 Rabbit 7

3 chicken 3 rabbit 2

4, 2, the solution of the chicken X head rule: buy black tea Xkg rule

1:2X+4(8—X)=20

2:2X+4( 1 1—X)=36

3:2X+4(5—X)= 14

4: 1 20 x+160 (14-x) = 2080,2,1,chickens and rabbits live in the same cage, with 8 heads and 20 legs. How many chickens and rabbits are there?

Set chicken x and rabbit 8-X.

2x+4(8-x)=20

2x+32-4x=20

2x= 12

x=6

There are 6 chickens, 2 rabbits, 2, Nishinagexuexieaode, 2 1. The chickens and rabbits are in the same cage, with 8 heads and 20 legs. How many chickens and rabbits are there respectively?

Chicken (4×8-20) and (4-2)

= 12÷2

=6

8-6 rabbits = 2 rabbits

2. Chickens and rabbits live in the same cage, 1 1 head, 36 legs. How many chickens and rabbits are there?

Chicken (4× 1 1-36)÷(4-2)

=8÷2

=4

Rabbit 1 1-4=7.

There are ..., 1, 1. There are 4 chickens and 3 rabbits in the cage.

2. 6 each

3.3 chickens and 2 rabbits

I don't know, 1, 1. Analysis: If there are X chickens, they have 2X feet; There are x chickens, 6-X rabbits and 4(6-X) rabbits with one foot.

.

If the number of chickens is x, the number of rabbits is 6-X.

2X+4(6-X)= 20 gives X=2.

Then there are 2 chickens, 6-2=4 rabbits.

2. Analysis: The same reason

If a chicken has x heads, a rabbit has 1 1-X heads.

2X+4( 1 1-X)= 36 gives X=4.

..., 1, 1 ...

2X+4(8-X)=20

2X+32-4X=20

2X= 12

X=6

8-X=8-6=2

Answer: There are 6 chickens and 2 rabbits.

2. Set X chickens and 1 1-X rabbits.

2X+4( 1 1-X)=36

2X+44-4X=36

2X=8

X=4

1 1-X = 1 1-4 = 7

Four chickens and seven rabbits.

3. Set X chickens, ..., 1, X chickens and 8-X rabbits.

2X+4(8-X)=20

2X+32-4X=20

2X= 12

X=6 (only)

Answer: There are 6 chickens and 2 rabbits.

There are x chickens and 1 1-X rabbits.

2X+4( 1 1-X)=36

2X+44-4X=36

2X=8

X=4 (only)

A: There are 4 chickens and 7 rabbits.

Set x chickens and 5-X rabbits.

2x+4 (5-x) = 14， 1， 1。 There are x chickens and 8-X rabbits.

2X+4(8-X)=20 Another idea is to lift all rabbits.

2X+32-4X=20 has two front legs, so each small animal has only two legs.

2x =12 ...,1,1.There are x chickens and (8-X) rabbits.

2X+4(8-X)=20

2X+32-4X=20

2X= 12

X=6

There are six chickens and two rabbits.

2. Suppose there are X chickens and (1 1-X) rabbits.

2X+4( 1 1-X)=36

2X+44-4X=36

2X=8

X=4

There are 4 chickens and 7 rabbits.

3. Suppose there are x chickens and (5-X) rabbits.

2X+4(5 ..., 0, 1, there are x chickens and y rabbits. Then two equations x+y=8 2x+4y=20 x=6 and y=2 can be listed.

2. Set X chickens and Y rabbits; Then the equations x+y =112x+4y = 36x = 4 and y = 7； can be listed.

3. Set X chickens and Y rabbits; Then the equation x+y=5 2x+4y= 14 x=3, y = 2；;

4. Set X Jin of black tea and Y Jin of green tea; The countable equation x+y =14120 x+16 ..., 0, the online solution of mathematics problems in the fifth grade of primary school (full-column equation).

I hope you heroes can solve my math problem. Thank you! & lt(￣︶￣)>；

1, chickens and rabbits live in the same cage, with 8 heads and 20 legs. How many chickens and rabbits are there?

2. Chickens and rabbits live in the same cage, 1 1 head, 36 legs. How many chickens and rabbits are there?

3. There are chickens and rabbits in the cage, ***5, 14 legs. How many chickens and rabbits are there?

4. Uncle Wang bought 120 yuan 1kg black tea and 160 yuan 1kg green tea, * * * 14 kg, and * * spent 2080 yuan. What kind of tea is he drinking? How many kilograms did Ge Ye buy?