Solve 2 math problems in the second year of junior high school, thank you

z=(c-a)y/(b-c)

Substitute x+y+z=0

2.If Xiaoying's family uses party A, Xiaoming's family is.

Excess part charge B is applied

a-5）*b= （1）

2) Syndicate (1) and (2).

Get b = square.

The first 0Substitute the other two formulas with x. Second, let the first one use 2x and the second one use 3xExcess water price y

2x_5>y=

3x 5>y = find y

x+y+z = x+x(b-c)/(a-b)+x(c-a)/(a-b)

x( 1 + b-c)/(a-b) +c-a)/(a-b) )x(1-1)=0.

2.The part exceeding 5 parties will be charged X yuan per party.

Since both of them use more than 5 cubic meters of water, so.

Solution: x =

Let x (a-b) =y (b-c) =z (c-a)=k, then x=ak-bk, y=bk-ck, z=ck-akx+y+z=ak-bk+bk-ck+ck-ak=0 set the part exceeding 5 square meters to charge x yuan per party, and the water consumption of Xiaoying's house and Xiaoming's house in July was 2a and 3a respectively

2a-5)x=

3a-5)x=

Solve this system of equations.

x = A: The part exceeding 5 parties will be charged yuan per party.

1. Let x (a-b) = y (b-c) = z (c-a) = k, that is, x ak-bk, y=bk-ck, z=ck-ak

then x+y+z ak-bk+bk-ck+ck-ak=02, set the part exceeding 5 parties to charge x yuan for each party, and the water fee for 5 parties is yuan.

Xiaoying's household water consumption should be (, Xiao Ming's household water consumption should be (, then [(:3 solves this equation to get x

The rule is that if the number of squares to be opened is enlarged or shrunk by a factor of 100, the result obtained is correspondingly expanded or shrunk by a factor of ten.

1.The surface area of a cube is 150 cm2

1) Find the edge length and volume of the cube.

150 6 = 25 square centimeters.

The edge length of this cube is 25 = 5 cm.

The volume of this cube is 5*5*5=125 cubic centimeters.

2) Now the wooden block is sawed into 8 small cube wooden blocks of the same size, and the edge length of each small cube is obtained.

125 8 = cubic centimeters.

Opening square = centimeters.

1.A cube has 6 faces, each with an area of 150 6=25, an edge length of 5, and a volume of 5*5*5=125

5 2= The edge length of each small cube is.

After the root number is opened, the square becomes longer.

Question 1: Original formula = (2a+b)(b-3a) 3-2(2a+b)(b-3a) 2=(b-3a)(2a+b)(b-3a) 2-2(2a+b)(b-3a) 2=(b-3a-2)(2a+b)(b-3a) 2

Question 2 (a+1) =(b-1) (1-b From the definition, a>=-1 b<=1 Left "=0 Description: b-1>=0

So b=1 a=-1

a^2009-b^2009=-1-1=-2

1: (2a+b)(b-3a)*3-(4a+2b)(3a-b)*2=(2a+b)(b-3a)*2(b-3a-2) Note: *3 and *2 represent the 3rd power and square respectively.

2: a+1=(1-b), (1-b)>=0 and b-1>=0, so b=1, a=-1, the equation is equal to -2

Question 1, Question 1.

Solution: Let the velocity of the second group be x m-min, then the velocity of the first group is m-450 x-450 (

can be obtained x = 5 So, the climbing speed of the two groups is 6 m min and 5 m min respectively The same is true for the second and first questions, and if the speed of the second group is x m min, then the speed of the first group is m min h x-h (

x=h (6t) can be obtained

Therefore, the climbing speed of the two groups is 6 m min and h (5 t) m min respectively The second problem is solved: if x machines are now produced per day, then the original daily production of x-50 machines is 450 (x-50) = 600 x

Solution x = 200

A: Now produce 200 machines per day.

Let the second group of velocities be V, then 450 V-450 will be Vs equal to 5, then the second group will be 6.

The second question is concocted in the same way, and time is also used to make an equal relationship.

h/v-h/(v+a)=t.Then a one-dimensional quadratic equation about v is obtained, and v=[-at+(a 2t 2+4aht) is obtained by using the root finding formula

It's the meaning of the root number, and you can write the root number at that time.

The next question is to produce x in one day, and now it is x+50

It is related to time.

600/(x+50)=450/x.Get x to be 150. It now produces 200 units a day.

1.Let the second group of velocities be x, then the first group is (unit: m min) (450 x)-15=450 (

x=5 means that the second group of velocities is 5m min, and the first group is 6m min(h x)-t=h (x+a).

tx^2+txa-ah=0

Find the root formula and substitute it.

2.Assuming that the original plan was to produce x units per day, it is now (x+50) 600 (x+50)=450 x

x = 150150 + 50 = 200 (Taiwan days).

The difference between the two groups of time is known from the known conditions, so if the second group of velocities is v, then 450 V-450 gets v=5, then the first set of velocities is: 6 m min.

The second question is the same reason, through the same time, it can be assumed that the original plan to produce X sets of machines; Column equations are solved.

1> Let the two quadratic integers be (x's square + ax+b), (x's squared + ax+c), multiplied to obtain: (x's fourth power + 2ax's cubic + (c+b+a's square) x's square + a(b+c)x+bc, because it is decomposed from the previous formula, it is equal to the front, so as to obtain: a's square + b+c=11; a(b+c)=6;p=bc;This gives b+c=2; p=bc;Because it is an integer, a, b are integers, and the maximum value of p is 1

2> Sorting out the equation gives [(m-n)x-3(m+n)] x squared -9) = 8x (x squared - 9), so m-n = 8, m+n = 0; m=4, n= -4, mn=-16;

x+bc, because it is decomposed from the previous formula, is equal to the previous one, so as to obtain: the square of a + b + c = 11; a(b+c)=6;p=bc;This gives b+c=2; p=bc;Because it is an integer, a, b are integers, and the maximum value of p is 1

2> Sorting out the equation gives [(m-n)x-3(m+n)] x squared -9) = 8x (x squared - 9), so m-n = 8, m+n = 0; m=4, n= -4, mn=-16;

22.The absolute values of x-2y+9 and x-y-3 under the root number are both 0 and opposite to each other, then both equations are 0 to obtain x-2y+9=0 x-y-3=0

The solution is x=15, y=12, then x+y=27

4x+5y=6m+3②

5-② x=7-m③ x＞0 7-m＞0 m＜7

y=2m-5 y 0 2m-5 0 m 5 2 In summary, 5 2 m 7

What calculator do you learn in this chapter?

Let the average percentage of price reduction be x

1（1-x）^3=1/3

x is approximately equal to. How can there be a cubic equation (either my method is wrong), there should be two imaginaries and I can't solve another problem.