Given that the line ax + y + A + 2 = 0 passes through a fixed point, the equation of the line passing through the fixed point and the origin is______ ．

Given that the line ax + y + A + 2 = 0 passes through a fixed point, the equation of the line passing through the fixed point and the origin is______ ．

From the straight line ax + y + A + 2 = 0, we can get a (x + 1) + (y + 2) = 0, let x + 1 = 0y + 2 = 0, we can get x = - 1, y = - 2 ﹣ the straight line ax + y + A + 2 = 0 always passes through a fixed point (- 1, - 2), ﹣ the linear equation passing through this point and the origin is y − 0 − 2 − 0 = x − 0 − 1 − 0, that is y = 2x so the answer is y = 2x

The equation of a straight line passing through the origin and tangent to the circle (x-3) ^ 2 + y ^ 2 = 1

C:(x-3)^2+y^2=1
C(3,0),r=1
L:kx-y=0
d=|3k-0|/√(1+k^2)=r=1
k=±√2/4
L:y=±(√2/4)x

The linear equation passing through point P (1, - 2) and parallel to X-Y + 1 = 0 is?

Let the analytic formula be X-Y + k = 0
If (1, - 2) is brought in, we can get "1 + 2 + k = 0", and the solution is: k = - 3
So: the analytic formula is x-y-3 = 0

In triangle ABC, the ratio of sine value is m: M + 1:2m, and the value range of M is calculated
A. M is greater than 2
B. M is less than 0
C. M is greater than - 1 / 2
D. M > 1 / 2

The sum of the two sides of the triangle is greater than the third side, and the difference between the two sides is less than the third side
2M+M>M+1
M > 1 / 2
Choose D

The speed ratio of car a and car B is 5:4. The two cars meet at the midpoint of 24 kilometers. How many kilometers are there between a and B?

24 × 2 ÷ (5 / 9-4 / 9) = 432km

If the set of integer solutions of inequality system about X is - 2
On the inequality system of X (1) xx-x-2 > 0 (2) 2XX + (2k + 5) x + 5K

Let's take x = - 2 and get K

Both passenger and freight cars leave from a and B at the same time. Passenger cars travel 98 kilometers per hour and freight cars 76 kilometers per hour. When they meet, passenger cars travel 132 kilometers more than freight cars
How many kilometers are there between a and B?

132÷【98/（98+76）-76/（98+76）】
=132÷11/87
=1044 km

Two calculation problems of plane vector
1：（-3）×4a=?
2:(2a+3b-c)-(3a-2b+c)=?
Note: A, B, C are vectors

1.-12a
2.-a+b

There are two classes in grade four, class A and class B. the number of class a accounts for 5 / 8 of the two classes. After nine people are transferred from Class A, the ratio of class A and class B is 2:3,
How many people are there in the two classes?
It's going to be solved by equations

2+3=5,
The total number of people: 9 (5 / 8-2 / 5) = 40,
Class A: 40x 5 / 8 = 25 people,
Class B: 40-25 = 15

How many of the natural numbers from 1 to 1000 excluding the number 3?

The total number of 3 bits is 10 × 9 = 90
There are 10 × 9 = 90 in total
There are three hundred, a total of 1 × 100 = 100
Then the total number of 3 is 90 + 90 + 100 = 280
Then there are 1000-280 = 720 numbers without 3