X-5y = - 3, 3x + 2Y = - 9,

X-5y = - 3, 3x + 2Y = - 9,

If Formula 1 is changed to x = 5y-3, substituting formula 2, we get 3 (5y-3) + 2Y = - 9, we get y = 0; substituting Formula 1, we get x = - 3

Solve the equations. 4-3x-2y + 3-2x-5y = 10.5-3x-2y-2-2x-5y = 1

1 / 3x-2y = a, 1 / 2x-5y = B, then find a and B, and then take it back to find X and y, and find the best answer

（1）{x-y=2 z-x=3 y+z=-1 （2）{x-y-z=2 3x+5y+7z=24 4x-y+2z=26
The answer to (1) is x = - 1, y = - 3, z = 2; (2) is x = 3, y = - 4, z = 5
The request writes the process, tomorrow must hand in!

1、x-y=2① z-x=3 ② y+z=-1 ③
From 2 to Z = 3 + x 4, substitute 4 for 3 to y = - 4-x 5, substitute 5 for 1 to x = - 1, substitute x = - 1 for 5 to y = - 4 + 1, y = 5, substitute x = - 1 for 4 to Z = 2
I'm a freshman in junior high school. I haven't learned the linear equation of three variables. I don't know if it's right

Factorization factor (x ^ 2 + 5x + 3) (x ^ 2 + 5x-23 + k)
The original formula is decomposed into (x ^ 2 + 5x-10), and the value of K is obtained

You copied it wrong. The original formula is (x ^ 2 + 5x-10) ^ 2
Consider x ^ 2 + 5x as a
Then (a + 3) (a-23 + k) = (A-10) ^ 2
That's what I'm going to do anyway

How to change the shape of a newspaper to increase its load bearing capacity

Roll into a cylinder~

To solve the equation: 3 / 2x + 1 - 6 / 5x-1 = 1 / 7 (2x + 14) = 4-2x 10 / 3 (200 + x) - 10 / 2 (300-x) = 300x25 / 9

-8*-

A and B are 40 kilometers apart. A starts for 1.5 hours and B starts again. A is behind and B is in front. They walk in the same direction. A is 8 and B is 6. How many hours does a catch up with B?
Why 6x + 40? Come on

Let a catch up with B in another x hours. When a catches up with B, the distance they travel is equal. B travels 6x kilometers, and the distance between the two 40 kilometers is equal to that of A. a Travels (1.5 + x) * 8 kilometers
So 6x + 40 = (1.5 + x) * 8 gives x = 14
So a 14 + 1.5 = 15.5 hours to catch up with B

Let A-B = - 2, find the value 2 of a square + b square -------- ab
Let A-B = negative 2. The teacher said that the final answer is 2. Let me give the reason

-ab=2
ab=-2
a-b=-2
(a-b)^2=a^2+b^2-2ab=2^2=4
a^2+b^2=4+2ab=4+2(-2)=0

39 * 37-13 * 11 simple method of factoring

39*37-13*11
= 13*(3*37 - 11)
= 13*(111 - 11)
= 13*100
= 1300

Pears and apples are 120 kg in total. The weight of pears is 12 kg more than that of apples. How many thousands of pears are there

Suppose the apple has x kg and the pear has 2x + 12 kg
x+2x+12=120
3x+12=120
3x=108
x=36
Pear 2x + 12 = 2 * 36 + 12 = 84kg
A: there are 36 kg apples and 84 kg pears