Xiaojun, Xiaoli and Xiaoming do their homework. Xiaojun uses three tenths of an hour more than Xiaoli, and Xiaoming uses one tenth of an hour less than Xiaoli How long is the difference? If Xiaoming uses one tenth of an hour more than Xiaoli, how long is the difference between Xiaojun and Xiaoming?

Xiaojun, Xiaoli and Xiaoming do their homework. Xiaojun uses three tenths of an hour more than Xiaoli, and Xiaoming uses one tenth of an hour less than Xiaoli How long is the difference? If Xiaoming uses one tenth of an hour more than Xiaoli, how long is the difference between Xiaojun and Xiaoming?

Suppose Xiaoli takes x hours, Xiaojun takes x + three tenths of an hour, Xiaoming takes X - one tenth of an hour, then the first question: x + three tenths - (x - one tenth) = two fifths of an hour; the second question: Xiaoming takes x + one tenth of an hour, then x + three tenths - (x + one tenth) = one fifths of an hour

In an exam, the sum of the scores of Xiaoming and Xiaoli is 184, the sum of the scores of Xiaoli and Xiaojun is 187, and the sum of the scores of Xiaojun and Xiaofei is 188
Now I know that Xiao Ming's score is more than Xiao Fei's. how many points did they get?

The equation 184-y = 188-y + 1 184-187 + y = 189-y-3 + 2Y = 189 2Y = 192 y = 96 is solved

Xiaojun and Xiaoming are 2.22 meters in height, Xiaoming and Xiaoli are 2.20 meters in height, Xiaojun and Xiaoli are 2.24 meters in height. How many meters are the three of them

Xiaojun: 1.13
Xiao Ming: 1.09
Xiao Li: 1.11

How to solve the quadratic equation of one variable
That is: 5x2-2x = 0, how to solve the quadratic equation of one variable? I have never been able to, and why does it have no constant term?

The quadratic equation of one variable is OK as long as the quadratic term is not zero
In this case, you can decompose the factor as X (5x-2) = 0
Connect x = 0 or x = 2 / 5

Do not change the sign and value of the fraction itself, so that the denominator of the first fraction in the following groups is the same as that of the second fraction
1/（a-4）,5/（4a-a²）

General score: 4a-a / (A-4) (4a-a & # 178;), 5 (A-4) / (A-4) (4a-a & # 178;)

[(x + 2 / 1y) ^ 2 + (X-2 / 1y) ^ 2] (2x ^ 2 + 2 / 1y ^ 2) where x = - 1. Y = 2

The original formula = (X & # 178; + XY + 1y of 4 & # 178; + X & # 178; - XY + 1y of 4 & # 178;) (2x & # 178; + 1y of 2 & # 178;)
=(2x & # 178; - 2 / 1y & # 178;) (2x & # 178; + 2 / 1y & # 178;)
=4X ^ 4-1y ^ 4 of 4
=4-4
=0

What is the number of solutions of nonhomogeneous linear equations with zero coefficient determinant?
Why?

There are no solutions or infinitely many solutions. It's better to ask questions. Otherwise, it's hard to look at this topic again. Reason: the necessary and sufficient condition for the solution of the system of non-homogeneous linear equations AX = B is R (a) = R (a, b). The necessary and sufficient condition for the unique solution of the system of non-homogeneous linear equations AX = B is R (a) = R (a, b) = n non-homogeneous line

﹙2－x﹚／﹙1－x﹚－﹙4－x﹚／﹙6－x﹚＝1－﹙x²－4﹚／﹙x²－7x＋6﹚
solve equations.

﹙2－x﹚／﹙1－x﹚－﹙4－x﹚／﹙6－x﹚＝1－﹙x²－4﹚／﹙x²－7x＋6﹚
Well organized
﹙x-2﹚／﹙x-1﹚－﹙x-4﹚／﹙x-6﹚＝1－﹙x²－4﹚／﹙x-1﹚（x-6）
Multiply both sides by (x-1) (X-6) to get
﹙x-2﹚（x-6）-﹙x-4﹚（x-1）=﹙x-1﹚（x-6）-﹙x²－4﹚
x²-8x+12-（x²-5x+4）=（x²-7x+6）-﹙x²－4﹚
Well organized
x=1/2

1. If the absolute value of a + B + 2 = 0, then a = --- then B=-----
2. If the absolute value of - (+ 3) + a = 0, then a=-----
3. If the absolute value of a = 3 and the absolute value of B = 1, then the absolute value of a + B is------

1. If the absolute value of a + B + 2 = 0, then a = 0, then B = - 2
2. If the absolute value of - (+ 3) + a = 0, then a = ± 3
3. If the absolute value of a = 3 and the absolute value of B = 1, then the absolute value of a + B is 2 or 4

Solving equations {2x + 5Y = 4, 7x + 21y = 21}

In equation 1, the term x3.5 is 7x + 17.5y = 14, so that equation 3, equation 2 minus equation 3 is 3.5y = 7, y = 2, x = - 3