Primary 6 Math Practice 26 2, 3, 5, 6, 7 How to write equations

Solution: Suppose Zhang Peng made x 3-pointers, then he made (9-x) 2-pointers.

3x＋2(9-x） =21

3x＋18-2x =21

3x-2x =21-18

x = 3 (3-point).

9-3=6 (2 points).

Solution: If there are x large balls, then there are (30-x) small balls. (Send the question in full next time) 11x 7 (30-x) = 266

11x-7x=266-210

4x=56x=14 (big ball).

30-14=16 (pcs) (of small balls).

Solution: If there are x science and technology groups, there will be (9-x) art groups.

5x+3（9-x）=37

5x-3x=37-27

2x=10x =5

9-5=4 (group) 5 5=25 (number of people in the science group) 4 3=12 (number of people) (number of people in the art group).

6 questions do not need to be written.

Solution: If you buy x basketballs, you buy (6-x) soccer balls.

42x+35（6-x）=231

42x-35x=231-210

7x =21

x =3 (number of basketballs).

6-3=3 (number of footballs).

It's gone, I'm tired to death, this is what I typed word by word, beg.

Solution: Let's say Zhang Peng made x three-pointers.

Zhang Peng made a (9-x) two-point shot.

3x+2x（9-x）=-21

Solve this equation.

Isn't this done with a hypothetical strategy? How to use equations?

If you need an arithmetic solution, look for me.

I'll write you a question.

Suppose 3x+3x=3x=

x=divided by 3x=

9 into 2 equals 18 21 minus 18 equals 3 3 minus 2 equals 1 3 divided by 1 equals 3

What kind of teaching version are you talking about (o Ahh

The person above the 4th question wrote it out, and he was right.

Solution: If there are x science and technology groups, there will be (9-x) art groups.

5x+3（9-x）=37

5x-3x=37-27

2x=10x =5

9-5=4 (group) 5 5=25 (number of people in the science group) 4 3=12 (number of people) (number of people in the art group).

Solution: If you buy x basketballs, you buy (6-x) soccer balls.

42x+35（6-x）=231

42x-35x=231-210

7x =21

x =3 (number of basketballs).

6-3=3 (number of footballs).

Solution: If player 2 answers x correctly, she answers 8-x incorrectly.

10x - 6（8-x）= 64

10x - 48 + 6x = 64 If you get x=7, you will answer 7 correctly, and 8-7=1 (answer) incorrectly

Solution: If player 1 answers x correctly, he answers 10-x incorrectly.

10x - 6（10-x）= 36

10x - 60 + 6x = 36 If you get x=6, you will answer 6 correctly, and 10-6=4 (lanes) incorrectly

Solution: If player 3 answers x correctly, he answers 16-x incorrectly.

10x - 6（16-x）= 16

10x - 96 + 6x = 16 If you get x=7, you will answer 7 questions correctly and answer 16-7=9 (channels) incorrectly

5.Solution: If the science and technology group is x people, then the art group is 37-x people.

x÷5 + 37-x）÷3 = 9

3x + 185 - 5x = 135 If you solve x=25, then there are 25 people in the science group and 37-25=12 (people) in the art group. Let's play with my classmates!

Solution: If there are x tricycles, then the bicycle manuscript will be rotten and there will be 3x+2(10-x)=26 bicycles

3x+20-2x=26

20+x=26

x=26-20

x =6

There are a total of 30 large and small steel balls in the box, with a total weight of 266g, each of which is known to be 11g of large steel balls and 7g of small steel mask beads. How many troubles are there in the box for Wang and renting large steel balls and small steel balls?

32÷x=64

x=32÷64

The principle of solving the equation is the same as that of x=1 2, which is based on the known and the unknown.

It's just that you should pay attention to the method of solving specific equations, and some equations have easy methods.

The ratio of height to bottom diameter is 3 to 1

The ratio of height to bottom radius is 6 to 1

Let the radius be r and the height be 6r

v=r*r*r=8

r=2a=2r=2*2=4cm

h=6r=6*2=12cm

s surface area = 4 * 12 * 4 + 4 * 4 * 2 = 192 + 32 = 224 cm2

The cylindrical surface area is the surface area of the cuboid.

If the radius of the bottom surface is x cm, the height is 6x cm

Cylinder volume: ·x 2·6x=

x=2, that is, the bottom side of the cuboid is 2 2=4cm

The height is 2 6 = 12cm

It turns out that the surface area of the box is.

2 (4 4+2 4 12)=224 cm 2 (The volume in the title seems to be!) )

Let the bottom diameter d=2r and the height be 6r

v=πr²·6r=

r=2（cm）

Surface area = 2 (2r) + 4·2r · 6r = 56r = 56 * 2 = 224 (cm).

Let the bottom radius be x, then the height is 6x, then x=2, the bottom diameter is 4, and the height is 12

The surface area of the box is diameter (base length) * diameter * 2 (both sides) + 4 (4 sides) * 12 (height, also long) * 4 (width, also base length).

1.There was a barrel of oil, the first time 1/3 of the total was used, the second time 2/5 of the total was used, and there were 16 kilograms of oil left in the barrel. How many kilograms of oil was in this barrel?

60 kg. 2.A canteen has a batch of rice, the original plan is to use kilograms per day, which can be used for 60 days, and the actual daily saving is 20% compared with the original plan, and how many days more than the original plan?

15 days. 3.There are 275 books on the shelves on three floors, 2 more books on the third floor than 3 times as many as on the second floor, 3 books less than 2 times the number on the second floor, how many books are placed on each of the three floors?

The second layer (275-2+3) (1+3+2).

46 copies. The first layer is 46 3 + 2 = 140 copies.

The third layer 46 2-3 = 89 copies.

1. Set the original x kilogram; Then there are:

x×(1-1/3-2/5)=16;

x=16÷(4/15)

x=60;So the original 60 kg.

2. If the number of multi-use days is x days, there are:

x=60×；

x=90÷x=75-60；

x=15；So use it for 15 more days.

3. Set up the second layer of x-book; Then there are:

3x+2+x+2x-3=275；

6x=276；

x=46；140 on the first floor; 46 books on the second floor; 89 books on the third floor.

1.The oil used to be x kilograms (1-1 3-2 5)x=16 4 15x=16 x=60

2. It took x days to solve the solution: 90 x= x=75 75-60=15 (days).

3. The second layer of the solution has x books: 3x+2+x+2x-3=275, 6x=276, x=46 (book), 3x+2=140 (book), 2x-3=89 (book).