Solve a math problem of a junior 3 equation and a 3 math equation

Solution: Set the preferential ticket for x and the ordinary ticket for (1200-x).

200 (1200-x) + 120x = 216000 solution: x = 300

Then: 300 concessionary tickets and 900 regular tickets.

The reason why I set the discount ticket is x is because it is easy to calculate, if the regular ticket is x, then it will be 120 (1200-x) trouble.

If you want to use a binary equation.

Solution: Ordinary tickets are x tickets, and preferential tickets are Y tickets.

1、x+y=1200

x+120y=216000

Change the formula 1 to x= or y= and bring in the formula 2, calculate one of them and bring in the formula 1, or the formula 1 *120 or *200, and then subtract the two formulas.

However, if there is no requirement to use binary equations, choose the first one, the second is too troublesome.

There are x ordinary tickets and ** y tickets.

x+y=1200 (1)

200x+120y=216000 (2)

1)*200-(2) 80y=24000

y=300 then x=900

There are x regular tickets and y discount tickets.

x+y=1200

200x+120y=216000

Solve the system of equations.

x=900y=300

Set 200 yuan for x sheets.

then 120 yuan for 1200-x sheets.

200x+（1200-x）*120=216000x=900

Set the number of regular tickets as x and the concession ticket as y

200x + 120y = 216000

x + y = 1200

x=900 y=300

900 regular tickets and 300 ** tickets.

Set the number of regular tickets as x and the concession ticket as y

x+y=1200

200x+120y=216000

The solution is x=900 and y=300

Set 120 yuan tickets, sold x tickets, 200 yuan tickets, sold y tickets: x+y=1200;120x+200y=216000；x=300 y=900

900 regular tickets and 300 ** tickets.

Let 200 be a and 120 be b, then a+b=1200, 200*a+120*b=216000, simultaneous equation, solve a=900, b=300

Summary. Hello, you can send me the equation.

Hello, you can send me the equation.

The second question of the teacher's question 8.

After factoring the cubic equation, I get the unary quadratic equation with b, and the derta value range is less than 0.

b＞-3，c＞2

2 is the only real root of the cubic equation x +bx+c=0, and it can be set that x +bx+c=(x+2)(x +mx+n) x +mx+n=0 has no real root.

So the problem becomes x +mx+n=0 without a real root, and the discriminant 0 of the root.

Put this equation (x+2)(x +mx+n) =x +(m+2)x +(2m+n)x+2n

Okay thank you. x + (m + 2) x + (2m + n) x + 2n = x + bx + c according to the one-to-one correspondence principle m+2=0, 2m + n = b2n = c, m=-2, n = c 2, c = 2b+8 can be solved

Finally, the discriminant expression of the root can be used to solve the inequality.

1, a 2 parts a-b

b 2 parts b - a 2 = (a 2-b 2) (a-b) = (ab) * (a-b) (a-b) = a

b2，2，（x

x^2/(1-x)

x1)*(x-1)/(x-1)-x^2/(x-1)(x^2-1-x^2)/(x-1)

1/(x-1)

1/(1-x)

3, (x1) 1 - (x 2-1) (x3) times (x 2-4x.)

3) Fractions (x 2-2x.)

1/（x1）-（x

3）/[x1)*(x-1)]*x-1)^2/[(x-3)*(x-1)1/（x1）-（x

3）/[x1)*(x-3)]

x-3)-(x

3)]/x1)*(x-3)]

6/[（x1)*(x-3)]

6/(x^2-2x-3)

1, a 2 parts a-b

b 2 parts b - a 2 = (a 2-b 2) (a-b) = (ab) * (a-b) (a-b) = a

b. The meaning of your title - I am not mistaken; When the numerator or denominator contains an algebraic formula with the "-" symbol, the numerator or denominator part should be bracketed) 1Solution: 6x 2-12x

7=6(x^2-2x

1=6(x-1)^2

B is 60 years apart when he is still behind A

Then the distance between the 2 cars is reduced by 130-60 = 70 km.

The time required is 70 (50-40) = 7 hours.

B is in front of A.

The distance change is 60

130 = 190 km.

The time is 190 (50-40) = 19 hours.

So it takes 7 or 19 hours.

5a=2.Set x cartons and Y woven bags.

8x+18y=1000 (1)64x+126y=7280 (2)(1)*8-(2).

64x+144y-64x-126y=8000-728018y=720

y=40x=35

8x+18y=1000-8 (1)64x+126y=7280 (2)(1)*8-(2).

64x+144y-64x-126y=7936-728018y=556

y=556 18=278 9 i.e. 30 and eight-ninths, indivisible, so his idea cannot be realized.

A+126A=950 then A=52, set X carton, Y weaving.

Then 1000 = 8x+18y

7280=64x+126y

x=35 and y=40 are calculated

3. The carton is 8 yuan per grapefruit, and the woven bag is 7 yuan per grapefruit, and the loss of money is 64b

7280+64b=64x+126y

1000=8x+18y

so 720-64b=18y

280=8x-64b

35+8b=x<

b There is no integer solution.

1》64a+126a=950；a=5；

2》1》C box carton and D bag woven bag.

64c+126d=7280;

8c+18d=1000;

c=35,d=40

2>64c+126d+0=7280;

8c+18d+8b=1000;

9d+32b is obtained, and then b=1,2,,,10 is brought in to get the solution.

Solution a+126a=950

A=52, set the carton with x boxes, and the woven bag with y bags 8x+18y=1000

64x+126y=7280

x=35y=40②

1: (64+126)*a=950 solution a=52:1, set the carton with x woven bag as y;

64x+126y=7280

8x+18y=1000

The solution is x=35 and y=40

a=52.Set up x box in carton and Y bag in woven bag. Equation 1: 64x+126y=7280 Equation 2: 8x+18y=1000 Solution: x=35, y=40

1.Solution (1): Set X days for construction A and day B.

30（1/x+1/

The solution is x=50, answer: A construction for 50 days, B construction for 75 days.

2): There seems to be a problem with the problem, if it is required to be completed within 60 days, then as long as A works for 50 days, the cost is 125,000 yuan.

2.Solve the problem of buying x basketballs and volleyball (36-x).

96x+64（36-x）≤3200

The x 25 solution inequality yields 25 x 28 number axes.

According to the title, x is a positive integer, x may be 26, 27, 28, then 36-x may be 8, 9, 10

There are x saplings of type A and 800-x saplings of type B.

24x+30（800-x）=21000

The solution is x=500,800-x=300

A: 500 seedlings of type A and 300 seedlings of type B.

2 solution: Set a maximum of x strains to buy.

Solution x 320

x maximum is 320

A: A can buy up to 320 plants.

3.Because the price of A is smaller than the price of B, the larger A is, the lower the total price.

So when x=320, ** is the lowest.

for, 320*24*yuan.

Answer: A selection of 320 plants, **the lowest, 19,488 yuan.

The landlord is satisfied, thank you!!

In the question, the root number 18 seems to have a problem, I think it should be + 18, the original equation is x 2-(3+ 2)x+3 2=0, that is, (x-3)(x-2)=0

So x=3 or x=2

If the title is correct, then the cross multiplication cannot be used, only the root finding formula can be used, and the result may still have the root number within the root number!

Make ...... with the root finding formula

a=1 b=-(3 + root number 2)c = - root number 18 into the formula. x1=(-b + b -4ac under root) 2ax2=(-b - b -4ac under root) 2a

Isn't there a bit of a problem with the title?,There's still a root number in the root number.,......

The question of the third year of junior high school will not be like this.

Both sides of the equation are multiplied by (x-2) (x-1) (x-3) (x-4) at the same time

Both sides can be divided at the same time.

The two sides of the equal sign are divided into each other:

5-x) (x-1)(x-2)=(5-x) (x-3)(x-4) i.e.: (x-1)(x-2)=(x-3)(x-4) without parentheses on both sides to obtain: 4x=10x=

(x+1)/(x-2)-(x+3)/(x-1)=(x-3)/(x-4)-(x-1)/x-3)

From the equation, we get: x-2≠0 , x-1≠0, x-4≠0 , x-3≠0 so x

Multiply both sides of the equation by (x-1)*(x-2)*(x-3)*(x-4) to get :)(x-1)*(x-3)*(x-4)(x+1)-(x+3)*(x-2)*(x-3)*(x-4).

3y^4+2y³-1=0；

3y^4+3y³-y³-1=0；

3y³（y+1）-（y³+1）=0；

3y³（y+1）-（y+1）（y²+1-y）=0；

y+1）（3y³-y²+y-1）=0；

y=-1 or 3y-y +y-1=0, the latter is difficult to solve using junior high school knowledge, if you will Cardin formula.