12. If | a | = | B |, then this event is inevitable. 2. In the solution of binary linear equations {4x + 3Y = 1, X and y are opposite to each other 12. If | a | = | B |, then () 2. If x and y are opposite to each other in the solution of binary linear equations {4x + 3Y = 1, then k = () {KX - (k-1) y = 3 3. It is known that the bivariate linear equation (A-1) x + (a + 2) y + 5-2a = 0 about X and Y. when a takes a value, we get an equation. The equation has a common solution, which is ()

12. If | a | = | B |, then this event is inevitable. 2. In the solution of binary linear equations {4x + 3Y = 1, X and y are opposite to each other 12. If | a | = | B |, then () 2. If x and y are opposite to each other in the solution of binary linear equations {4x + 3Y = 1, then k = () {KX - (k-1) y = 3 3. It is known that the bivariate linear equation (A-1) x + (a + 2) y + 5-2a = 0 about X and Y. when a takes a value, we get an equation. The equation has a common solution, which is ()

If | a | = | B |, then (a = b), this event is inevitable
If x and y are opposite to each other in the solution of the system of quadratic equations {4x + 3Y = 1, {KX - (k-1) y = 3, then k = (2)

In the system of quadratic equations 4x + 3Y, X and y are opposite to each other=

This is a binary linear algebra

It takes 5 seconds for the car to stop from braking. During this period, the distance of the car every 1 second is 9 m, 7 m, 5 m, 3 m and 1 m respectively. (1) calculate the average speed of the car in the first 1 s, the first 3 s, the first 4 S and the whole journey. Which of the five average speeds is closer to the instantaneous speed of closing the throttle: is it slightly larger or smaller than this instantaneous speed? (2) What is the average speed of the car in the last second? What is the final speed of the car?

(1) The displacement of the car in the first 1 s is X1 = 9m, the displacement of the car in the first 3 s is X3 = 9 + 7 + 5m = 21m, the displacement of the car in the first 4 S is X4 = 9 + 7 + 5 + 3M = 24m, and the displacement of the whole car is x = 9 + 7 + 5 + 3 + 1m = 25m, so the average speed of the car in the first 1 s is. V1 = x1t1 = 91m / S = 9m / s

The distance between a and B is 880km. The car starts from A. two hours later, the bus starts from B and faces each other. Four hours later, the two cars meet,
It is known that cars travel 20 kilometers more per hour than buses. Q: how many kilometers do buses travel per hour?

If the bus travels x kilometers per hour, the car travels (x + 20) kilometers per hour
880=(x+20)*2+(x+20+x)*4
880=2x+40+8x+80
880=10x+120
10x=880-120
10x=760
x=76

It is known that a = - 3, B = - 5, C = 4, if (a + 1) ∧ 2 + | B-2 | = 0, find the value of a∧ 2008 × B ^ 3

1*8=8

1 / 2x - [(2x-2 / 3Y & # 178;) - (- 3 / 2x + 1 / 3Y & # 178;)], where x = 1 / 4, y = - 1

Original formula = 1 / 2x - (2x-2 / 3Y & # 178; + 3 / 2x-1 / 3Y & # 178;)
=1/2x-(7/2x-y²)
=1/2x-7/2x+y²
=-3x+y²
=-3×1/4+(-1)²
=1/4

Two piles of sand, the first pile is 37 tons more than the second pile. It is known that the first pile is 4 tons more than the second pile. How many tons of sand are there in each pile?

If the first pile of sand is x tons, the second pile of sand is X-37 tons
x-4(x-37)=4
x-4x+148=4
3x=144
x=48
x-37=11
The first pile of sand is 48 tons, and the second pile of sand is 11 tons

1. What is the square of (x + 2y-z) (c-2y-z) - (x + Y-Z)?
3. If a + B = 7, ab = 12, what is the value of a square - AB + b square?
4. Given that 3 times the square of x-x-3 = 0, then what is the square of X + 1 / 2 of X?
5. When x is any real number, what is the value of the algebraic formula x square-4x + 5?
6. Given that X and y satisfy (x + 2Y) (x-2y) = - 5 (y-6 / 5), 2 times x times (Y-1) + 4 (2 / 2 x-1) = 0, find the values of the following formulas: (1). (X-Y) square, (2) x quartic power + y quartic power - X-Y square
On these six questions, the faster the better, not necessarily all out, please mark the question number!

1. Original formula = (x-z) ^ 2 - (2Y) ^ 2 - (x-z + y) ^ 2
=(2x-2z+y)(-y)-4y^2
=-2xy+2yz-y^2-4y^2
=-2xy+2yz-5y^2
2、x=4/3 1/x=3/4
1/x^2-2/x+1=9/16-3/2+1=1/16
3、a+b=7
(a+b)^2=a^2+2ab+b^2=49
a^2-ab+b^2=49-3ab=49-3*12=13
4、3x^2-x-3=0 3x-1-3/x=0
3(x-1/x)=1 x-1/x=1/3
(x-1/x)^2=x^2-2+1/x^2=1/9
x^2+1/x^2=1/9+2=19/9
5. Let x ^ 2-4x + 5 = y
Then x ^ 2-4x + 5-y = 0
△=16-20+4y≥0
∴y≥1
That is, the value of the algebraic formula x-4x + 5 is ≥ 1, and the minimum value is 1
6. From (x + 2Y) (x-2y) = - 5 (y-6 / 5)
We get x ^ 2 + y ^ 2 = 25 / 6
From 2 times x times (Y-1) + 4 (1 / 2 x-1) = 0
We get xy = 2
(1)(x-y)^2=x^2-2xy+y^2=25/6-2*2=1/6
(2)x^4+y^4-x^2y^2=(x^2+y^2)^2-3x^2y^2
=(25/6)^2-3*2^2
=625/36-12
=193/36

Let the logarithm of three be equal to a, the third power of one-third zero be equal to B, and the third power of two be equal to C, then the size relationship of a, B, and C is?

Obviously, C = 8 > 1 > 1 to the power of 0.3 > 0 > log3 (bottom half)

The fruit shop brought in a batch of fruits and sold 3 / 10 of them on the first day and the remaining 4 / 5 on the second day. There were 168 kg left. How many kg were sold on the second day?

3 / 10 of unit 1 sold on the first day
On the second day: (1-3 / 10) * 4 / 5 = 7 / 10 * 4 / 5 = 28 / 50 = 14 / 25
The rest in unit 1: 1-3 / 10-14 / 25 = 7 / 10-14 / 25 = 35 / 50-28 / 50 = 7 / 50
The total amount of this batch of fruit is 168 / 7 / 50 = 1200 (kg)
The fruit sold the next day is 1200 * 14 / 25 = 672 (kg)