Mathematics Hurry up! Please answer in detail, thank you 3 12 23 27

29.Let's assume that my current age is x, and my son y, x=3y

x-5=5(y-3)

Solution: x=30, I am now 30

29.If 5 years ago, my son's age was x, my age was 5xToday I am 5x+5 and my son is x+5According to the title, the equation 5x+5=3(x+5) can be listed

The solution is x=5, so 5x+5=30So I'm 30 years old now.

30。Suppose the younger brother is going to pick x bricks, then the older brother is going to pick (26-x) bricks.

First brick grab: younger brother (x 2) older brother (26-x 2) blocks.

Second brick grab: Younger brother (x 4+13) Older brother (13-x 4) blocks.

The third brick grab: younger brother (x 4+8) and older brother (18-x 4) blocks.

The last columnable equation is: 18-x 4-2=x 4+8x 2=8x=16

So at first, the younger brother was going to pick 16 bricks.

The son is x and I am 3x 3x-5=5 (x-5) and I get x = 10 inverted pile method The elder brother has two more pieces than the younger brother 14 12, and the younger brother gives the elder brother 5 pieces 9 17

Snatched half from my brother 18 8

Snatched half of 10 16 from his brother

The younger brother wanted to pick sixteen pieces.

29） 5（x-5)=(y-5)

Column system of equations {3x=y

Solution: x=10 y=30

So I'm 30 years old now.

Untie; Let the original speed be x kilometers per hour.

7x=(x+20)5

7x=5x+100

2x=100

x = 50A. The distance between B and B: 50x7=350 (km).

The first side: 5m+2n

The second edge: [5m+2n-(2m-n+1)] 2=(5m+2n-2m+n-1) 2=(3m+3n-1) 2

The third edge: 50-[(5m+2n)+(3m+3n-1) 2]=50-[5m+2n+3m 2+3n 2-1 2].

50-(13m/2+7n/2-1/2)

99/2-(13m+7n)/2

1.Let a be the difference between the opposite of -4 and the absolute value of -12, and b be the number 5 greater than -6.

a=-8,b=-1

Find the values of a-b, b-a; a-b=-7, b-a=7 Explore the relationship between a-b and b-a. a-b if|a|=7，|b|=3, and a 0, b 0, then a-b=10, a=7, b=-3

4.If |a|=7，|b|=3, and a and b have different signs, then a-b = 10 or -4

1、a=-(-4)-|12|

8b=-6+5

1a-b=-8-(-1)=-7

b-a=-1-(-8)=7

a-b=-(b-a)

That is, a-b and b-a are inverse numbers to each other.

3、｜a|=7, and a is greater than 0, so a=7

b|=3, and b is less than 0, so b=-3

a-b=7-(-3)=10

4、a=±7，b=±3

A, B variants.

So a-b = 7 - (-3) = 10

or a-b = -7-3 = -10

1)a=4-12=-8,b=-6+5=-1,a-b=-7,b-a=72)a-b=-b+a=-(b-a)

4)a>0,|a|=7, so a=7, b 0, |b|=3, so b=-3, a-b=10

5) If A and B have different signs, then there is a 0, B 0 or A 0, B 0A 0, |a|=7, so a=7, b 0, |b|=3, so b=-3, a-b=10

a＜0,|a|=7, so a=7, b 0, |b|=3, so b=-3, a-b=10

then a-b = 10 or -10

a=-(-4)-丨-12丨=4-12=-8b=(-6)+5=-1

a-b=（-8）-（1）-8+1=-7

b-a=（-1）-（8）=-1+8=7

a-b and b-a are inverse numbers to each other.

The number 2 smaller than -3 is -5

The number smaller than 3 and 4 is -1

1. The opposite of "-4"Yes 4. The absolute value of -12 is 12,. a=4-12=-8 。"b is a number greater than -6 by 5", b = -6 + 5 = -1.

1) a-b=-8-(-1)=-7, b-a=-1-(-8)=7(2) a-b2, "number of 2 less than -3", -3-2=-5 "number of 4 less than 3", 3-4=-1

3. a=7 ,b=-3 a-b=7-(-3)=104, a=7,b=-3 or a=-7, b=3 a-b=7-(-3)=10 or a-b=-7-3=-10

1. a=-8, b=-1 Answer: (1)-7, 7(2) a-b and b-a are inverse numbers to each other.

3. A=7, B=-3Answer 10

or -10

), a-b=-7 b-a=7 2) are inverse numbers of each other 2, -5 -1

3、a-b=10

4. a-b = 10 or -10

x+3+4 = 2y-x-2+3, ie.

y = x + 3

The diagram is: 3 4 x

2 x+3 a

x+6 c b

x+3+4+c = x+3+4, i.e. c = 0x+3-2+a = x+3+4, i.e. a = 6x+6+0+b = x+3+4, i.e. b = 1 The graph is:

3 4 x2 x+3 6

x+6 0 1

Obviously, the requirement for x, is not enough. It should be that the oblique 3 numbers are also equal, so there is x+6+x+3+x=x+3+4

If we get x=-1, then y = 2

Fill in: 3 4 -1

First, according to the meaning of the question, find out the system of binary equations only about x, y, note that these two equations can only contain x, y can not have other letters, 3+4+x=3-2+2y-x, 3+4+x=2y-x+y+x; After simplification, the new system of equations is obtained as: x-y=-3, x-3y=-7 is solved to get x=-1, y=2, x=-1, y=2, and then the value of x,y is filled in ** to get 34

1-22a5cb At this time, you can observe that the sum of the three numbers in the first horizontal row is 6, then it means that the sum of the three numbers in the other horizontal rows, vertical rows, and diagonal diagonals should be 6, according to which you can calculate that the numbers represented by the other three letters are a=6, b=1, c=0, and the formula cannot be displayed above, so I can only write the above equation as two in parallel, and you can write it yourself in the form of a system of equations.

b=-3 And then I'm going to think about it, get off work first.