1. 2X + 3Y = 1,2,2 of X + y + 4 of X-Y = 4 3x-5y=68 4（x+y)-3(x-y)=12

1. 2X + 3Y = 1,2,2 of X + y + 4 of X-Y = 4 3x-5y=68 4（x+y)-3(x-y)=12

The formula (1) is × 3, and the formula (2) is × 2
6X + 9y = 3 (3), 6x-10y = 136 (2)
(3) (2) 19y = - 133
                  y=-7
Substituting y = - 7 into (1) yields x = 11

`Mathematics to the process, thank you, to use binary linear equation to express``
Two objects move on a circle with a circumference of 100 meters. If they move in the same direction, they meet every 20 seconds. If they move in the opposite direction, they meet every 4 seconds`

Let the velocities of the two objects be V1 and V2 respectively
In the same direction: V1 * 20-v2 * 20 = 100
Opposite: V1 * 4 + V2 * 4 = 100
The solution of the two equations is V1 = 15, V2 = 10
So the speed of objects in the coming year will be 15m / s and 10m / s respectively

If the equation (M2-1) x2-2 (M + 2) x + 1 = 0 has real roots, then the value range of M is ()
A. M ≥ − 54 and m ≠± 1b. M ≥ − 54C. M ≤− 54 and m ≠± 1D. M ≤− 54

When the equation (M2-1) x2-2 (M + 2) x + 1 = 0 is a quadratic equation of one variable, M2-1 ≠ 0, that is, m ≠ ± 1. ∵ the equation (M2-1) x2-2 (M + 2) x + 1 = 0 has a real root, and the solution is m ≥ - 54

Mathematical problems to the process, thank you, to use binary linear equation to set up
There are 8 rounds of a middle school football match (i.e. each team needs 8 games) ` win one game and get 3 points' ` draw one game and lose one game and get 0 points' ` Red Star middle school football team draws two times of the number of negative Games' and gets 17 points' in total. How many games should the pair win?

If x field is flat and Y field is better, then 1 / 2x field is negative
x+y+1/2x＝8
x＋3y＝17
We get x = 2
y＝5
So, 1 / 2x = 1
A: five wins