The problem of solving 20 binary linear equations and 20 unitary linear inequalities

The problem of solving 20 binary linear equations and 20 unitary linear inequalities

(1) 66x + 17Y = 3967 25X + y = 1200 answer: x = 48 y = 47 (2) 18x + 23y = 2303 74x-y = 1998 answer: x = 27 y = 79 (3) 44x + 90Y = 7796 44x + y = 3476 answer: x = 79 y = 48 (4) 76x-66y = 4082 30x-y = 2940 answer: x = 98 y = 51 (5) 67x + 54y = 8546 71x-y =

What are the general steps of solving binary linear equations and hospital linear inequalities?

The main idea of solving the binary linear equations is to eliminate the elements, change the binary into the unitary linear equation, then remove the denominator, remove the bracket, shift the term, merge the similar terms, and change the coefficient to 1
The methods of solving linear inequality and equation of one variable are almost the same. There are also some methods: to remove denominator, to remove bracket, to shift term, to merge similar terms, and to change coefficient to 1
[the biggest difference is that when both sides of the inequality are divided by the same negative number that is not zero, the direction of the inequality sign should be changed. Pay close attention to it]

English singular sentence five, plural sentence five, use there is or there are, but also Chinese!

Singular sentence:
1.There is a pencil on the desk
There is a pencil on the desk
2.There is an apple in the tree.
There is an apple on the tree
3.There is a bird flying in the sky.
There is a bird flying in the sky
4.There is a bookstore near the bus station.
There is a bookstore beside the station
5.There is a car over there.
There is a car there
Plural sentence:
1.There are some books on the bookshelf.
There are some books on the shelf
2.There are many children playing football on the playground.
There are many children playing football on the playground
3.There are many needy families in our village.
There are many poor families in our village
4.There are many cedars in this park.
There are many cedar in this park
5.There are rows of tents at the foot of the mountain.
There are several rows of tents at the foot of the mountain

The height of a cylinder is 8 cm, and the surface area of the cylinder will be reduced by 25.12 square cm after cutting off a section of 2 cm long

The surface area of the cylinder is equal to the two bottom areas plus the side area. Because the height is reduced by 2 cm, the less 25.12 square cm is the side area. The side area is the circumference of the circle multiplied by the height, so use 25.12/2 = 12.56 cm (circumference of the circle) radius of the circle = perimeter divided by (2 * 3.14) radius = 12.56 / 6.28 radius = 2 cm

May I ask the C language program for the greatest common divisor and the least common multiple of any number“

#include
void main()
{int a,b,num1,num2,temp;
scanf("%d%d",&num1,&num2);
if(num1

In the isosceles triangle ABC, ab = AC, the center line BD on AC divides the circumference of the triangle into two parts: 21 cm and 12 cm, and calculates the length of each side of the triangle
Because that's why I wrote it

Let AB = x ∵ AB = AC = x ∵ BD be the middle line of AC ∵ ad = BD = 1 / 2Ac = 1 / 2x. From the meaning of the title, we can know: ab + ad = 12 BC + CD = 21 ∵ ad = CD ∵ BC + CD - (AD + AB) = BC + cd-ad-ab = bc-ab = bc-ab = bc-x = 21-12 BC + CD = 21 ∵ AB + AC + BC = 21 + 12 = 33 ∵ x + X + X + X + X + 9 = 33, we get x = 8, then BC = x + 9 = 8 + 9 = 17 ∵ the lengths of the three sides are 8cm, 8cm and 17cm respectively

The greatest common divisor of 45 and a number is 15, the least common multiple is 180, and a number is?

The maximum convention is 15. Indicate that a number is a multiple of 15
And a divisor of 180
So a certain number can be 15, 30, 45, 60, 90, 180
After testing, only 60 meet the conditions

It is proved that if y = K1X + B1 is perpendicular to y = k2x + B2, then K1 * K2 = - 1
Be strict! Be strict, be strict!
Two methods are used
1. No induction formula
2. Using induction formula
3. In the same plane

If we use geometric method, we can prove that K1 = Tan α, K2 = Tan β. If two straight lines are perpendicular, it means α + 180 ° - β = 90 °, that is, Tan α * Tan β = - 1 α β are the angles between two straight lines and X axis

Unit 12 words in English book of grade seven volume one

Unit 121. Subject____________ 2. Science____________ 3. Sports____________ 4. Because____________ 5. Description, description____________ 6. Word, word____________ 7. Teachers____________ 8. Ladies____________ 9. Partner, partner____________ 10. City_________ ...

It is known that the square + 4xN + m of the parabola y = NX intersects with the x-axis at two points a (- 1,0) and B (x2,0), and intersects with the positive semiaxis of the y-axis at C. the vertex of the parabola is d,
And △ ABC = 1

Solution; ∵ the square of parabola y = NX + 4xN + m intersects with X axis at two points a (- 1,0), B (x2,0)
∴-1+x2=-4 ∴x2=-3
At the same time, n-4n + M = 0 - 1 * (- 3) = 3 = m / n
∴m=3n
Vertex (- 2, - n)
∵△ABC=1
∴1/2*|-1-(-3)|*|-n|=1
N = - 1 or 1
The parabola y = - X & # 178; - 4x-3 or y = x & # 178; + 4x + 3