A problem of solving quadratic equation of one variable in the third day of junior high school X & sup2; - 2 | x | + 2 = m has exactly three real roots, What is the value of M? ∵ X & sup2; = | x | & sup2;; the original equation can be reduced to | x | & sup2; - 2 | x | & sup2; + (2-m) = 0, ∵ the equation has three real roots, | there must be one real root | x | = 0, (otherwise the equation has four real roots!); 2-m = 0, M = 2 What I don't understand is why | x | = 0?

A problem of solving quadratic equation of one variable in the third day of junior high school X & sup2; - 2 | x | + 2 = m has exactly three real roots, What is the value of M? ∵ X & sup2; = | x | & sup2;; the original equation can be reduced to | x | & sup2; - 2 | x | & sup2; + (2-m) = 0, ∵ the equation has three real roots, | there must be one real root | x | = 0, (otherwise the equation has four real roots!); 2-m = 0, M = 2 What I don't understand is why | x | = 0?

Let | x | = y, then the original equation is y ^ 2-2y + 2-m = 01. The equation has no real roots. 2. The equation has two identical real roots. If | x | = y ≠ 0, then the original equation has two different real roots (when y > 0) or no real roots (y < 0). If | x | = y = 0, then the original equation has only one root 03

Please master to solve a third day of one variable quadratic equation problem
2 (X-2) square = 4-x square
Can write the process best!

2(x-2)^2=4-x^2
2(x-2)^2+x^2-4=0
2(x-2)^2+(x-2)(x+2)=0
[2(x-2)+x+2](x-2)=0
(3x-2)(x-2)=0
x1=2/3,x2=2

Application of binary linear equations
A says to B, "when my age is your present age, you are only 4." B says to a, "when my age is your present age, you will be 61." how old are a and B?

Let a be x years old and B be y years old
x-y=y-4
61-x=x-y
The solution is: x = 42, y = 23
A: A is 42, B is 23

{3x+5y=-20 4x-5y=-15

{3x+5y=-20 1
4x-5y=-15 2
1 + 2
7x= -35
x= -5
Substituting x = - 5 into 1 gives:
-15+5y= -20
5y= -5
y= -1
The solutions of the equations are: x = - 5, y = - 1

A school held an autumn sports meeting. Several students bought several bottles of mineral water. Each one had six bottles left, and each one had two bottles. How many bottles of water did they have?

Set the number of students as X and list the equation
x+6=2x-4
x+6-6=2x-4-6
x=2x-10
According to subtraction = subtracted - difference
The result is: 2x-x = 10
x=10
So, there are 10 students, then there are 10 + 6 = 16 bottles of water
(x + 6 and 2X-4 denote the number of bottles of water)

All positive integer solutions satisfying x + y = 43x − 2Y ≤ 8 have ()
A. Group B, group C, group D

The transformation of solution (1) into x = 4-y (2) to get 3 (4-y) - 2Y ≤ 8 (2) to get y ≥ 45 (1) into y = 4-x (2) to get 3x-2 (4-x) ≤ 8 (4-x) ≤ 8 (2) to get x ≤ 165  all positive integer solutions satisfying x + y = 43x-2y ≤ 8 have three groups: y = 1x = 3, y = 2x = 2, y = 3x = 1

What's your favorite food and drink? My favorite food and drink are hamburger and coke

What are your favourite food and drinks?
Hamburgers and coke
My favorite food and drinks are hamburgers and coke.
Baidu education team [Haina Baichuan group] answers for you

(1.1 times 20.83 minus (12.8 minus 8) times 1.1) divided by (2 / 3 plus 1 / 4)

(1.1 times 20.83 minus (12.8 minus 8) times 1.1) divided by (2 / 3 plus 1 / 4)
=1.1*(20.83-12.8+8)/(2/3+1/4)
=1.1*16.03/(11/12)
=12*16.03/10
=19.236
[questions are welcome]

AB car starts from a to the same highway at the same time. A is 8000 meters faster than B. A arrives at B 20 minutes earlier than B. when B arrives at B, a goes again, 24000 meters to C, seeking the distance between a and B

The speed of car a is 24 ÷ (20 / 60) = 72 km / h,
The speed of car B is 72-8 = 64 kmh,
Therefore, the distance between a and B is (20 / 60) / (1 / 64-1 / 72) = 192 km

(1 × 2) 2 ＋ (2 × 3) 2 ＋ (3 × 4) 2 + (2002 × 2003) 2 = how much

(1 × 2) 2 ＋ (2 × 3) 2 ＋ (3 × 4) 2 + (2002 × 2003) 2 = 2 [(1 × 2) 1 + (2 × 3) 1 + (3 × 4) 1 + (2002 × 2003) 1 / 2] = 2 [(1 / 1-2 / 1) + (1 / 2-3 / 1) + (1 / 3-4 / 1) ＋...