It is known that the solutions of the equations {2x + 5Y = 2, ax by = - 4 and {3x-y = 20, BX ay = 4 are the same, Find the value of (2a + b) times as 2013

It is known that the solutions of the equations {2x + 5Y = 2, ax by = - 4 and {3x-y = 20, BX ay = 4 are the same, Find the value of (2a + b) times as 2013

2X + 5Y = 2 (1) 3x-y = 20 (2) (1) + (2) × 5: 2x + 15x = 2 + 100; 17x = 102; X = 6; bring in (1) to get: 2 × 6 + 5Y = 2; 5Y = - 10; y = - 2; so there are: 6A + 2B = - 4 (3) 6B + 2A = 4 (4) (3) × 3 - (4) to get: 18a-2a = - 12-4; 16A = - 16; a = - 1; bring in (3) to get: - 6 + 2B = - 4; 2B =

It is known that the solutions of the system of equations (x + y = 3 ax by = 1) and (2x + y = 4 BX + ay = 12) about X and y are the same, so we can find the solutions of a and B

If the solutions are the same, they can be solved simultaneously
X+Y=3
AX-BY=1
2X+Y=4
BX+AY=12
Then, two equations with constant coefficients are used
X+Y=3
2X+Y=4
We find that x = 1, y = 2
10. Y is substituted as a coefficient
AX-BY=1
BX+AY=12
The equation is as follows
A-2B=1
2A+B=12
The solution is that,
A=5
B=2
The problem has to be solved

Given that the solution of the system {ax + by = 4, BX + ay = 5 satisfies x + y = 3, then a + B =? Please write the process,

Equation (1) + (2) leads to
ax+by+bx+ay=9
ax+ay+bx+by=9
a(x+y)+b(x+y)=9
(a+b)(x+y)=9
∵x+y=3
∴a+b=3

Simplification; - 2 (2XY + 2x) + 3 (- 2xy-5x)
(- 1 / 3 + m squared n + m squared) - (2 / 3-m squared N-M cube)

-2(2xy+2x)+3(-2xy-5x)
=-4xy-4x-6xy-15x
=-10xy-19x
(- 1 / 3 + m squared n + m squared) - (2 / 3-m squared N-M cube)
=-1/3+m²n+m²-2/3+m²n+m²
=2m²n+2m²-1

A and B practice running on the 400 meter track. If they run in the same direction at the same time, they can meet each other every 3 minutes and 20 seconds. If they run in the opposite direction at the same time, they can meet each other every 40 seconds

Let the velocities of a and B be x and Y respectively
The meeting of reverse running shows that the two people run 400 meters in one lap in 40s
Running in the same direction means that after 3 minutes and 20 seconds, that is, 200 seconds, the fast lap just exceeds the slow lap
The reverse running is (x + y) times 40 = 400
When running in the same direction, (X-Y) times 200 = 400
So x = 6, y = 4
The speed of the two men is 6m / s and 4m / s respectively
Learn to come on, come on~

1. There are 6 different story books and 1-8 issues of children's literature on the desk. Xiao Fang chooses two at will. How many different choices does she have
2. There are five banknotes: 1 yuan, 2 yuan, 5 yuan, 10 yuan and 20 yuan. Now you can take any two of them to form different currency values

1. A total of 14, choose the first book, there are 14 possibilities, the second book left 13 possibilities, so the possibility should be 14 * 13, but the two books have no difference in order, choose a and B, or choose B and a, is the same, so finally divided by 2, a total of 14 × 13 △ 2 = 91 kinds of 2

Simple calculation of 3 / 45 * 44

First about points, get 15 * 44 points of 1, take a 2 out of 44, get 30 * 22 points of 1, now oral calculation is OK

1. A truck started from Carrefour, walked 4 kilometers eastward to Xiaobin's house, continued to walk 2.5 kilometers to Xiaoyu's house, walked 12.5 kilometers westward to Xiaoming's house, and finally returned to Carrefour. Xiaoming's house was () kilometers away from Xiaobin's house, and the truck ran () kilometers in total
2. The difference between the two readings on the counter of the electricity meter is the electricity consumption during this period. At 0:00 on June 1, the reading of the electricity meter of a family is 121 degrees, and at 24:00 on June 7, the reading of the electricity meter is 163 degrees. From the reading of the electricity meter, it is estimated that the total electricity consumption of the family in June is 121 degrees_____ Degree
3. A bus has 56 seats. It starts empty. There are 2 passengers at the first stop, 4 passengers at the second stop, and 6 passengers at the third stop. It goes down in turn and gets on at the n stop_____ Four passengers____ After the station, the train was full of passengers
Explain why

1）10,25
2）180
3）2N,7

1+2+3+4+5.+99+100+101+102+.+1000+1001+1002 +1003+.+10000=?

10000/2×（1+10000）=5000×10001=50005000

18 x minus 32.5 times 18 equals 57.6 how to solve the equation

18x-32.5*18=57.6
18x-585=57.6
18x=57.6+585
18x=642.6
x=35.7