Urgently, please help solve 3 1 yuan 2 application problems

Question 1:

You've got the correct equation that 2x 2-28x=0 (here is 2x 2 instead of 2x squared) is solved by the root equation (-b+28) 2a and (-b-28) 2a to be 14 and 0, i.e. don't cut to make the area 196

Question 2: The answer you gave has a problem, and there are many parentheses, take a look at my:

1/2p^2+p(m+2)/2

1/2[p^2-p(m+2)+(m+2)^2/4]+(m+2)^2/8

1 2[p-(m+2) 2] 2+(m+2) 2 8, so when p=(m+2) 2, the maximum value is taken.

There is another question.

Solution: Establish a coordinate system with a as the origin, the east-west direction as the x-axis, and the north-south y-axis.

point a coordinates (0,0).Point b coordinates (0,-90).After t, ** coordinates (20t, 0), reconnaissance ship (0, -90 + 30t).

To be detected, (20t) 2+(-90+30t) 2<=50 213t 2-54t+56<=0

13t-28)(t-2)<=0

2<=t<=28/13

Earliest t=2

Question 1: The wrong is in the result, you have already got the equation.

2x2-28=0 (here 2 times x squared instead of 2x squared).

So we can get x=14 or x=0 (rounded).

I'll come to the last question.

No, 3 hours had passed by the time the electronic reconnaissance ship sailed from south to north at a speed of 30 knots to point B, at which point ** had reached 60 nautical miles due east of point A, and 50 was less than 60

So no.

1。If the length of the bamboo pole is x feet, the width of the door is x-4 feet, and the height of the door is x-2 feet.

According to the Pythagorean theorem there are:

x-2)²+x-4)²=x²

i.e. x -12x + 20 = 0

i.e. (x-2)(x-10)=0

x1 = 2 (rounded), x2 = 10

That is, the length of the bamboo pole is 10 feet.

x1=rounded), x2=

3。Sales in March = 100 (1-20%) = 800,000.

Let's assume that the average growth rate in April and May is x

Then the sales volume in May = 80 * (1 + x) * (1 + x) = that is, (1 + x) 2 =

So 1+x=

x=4.The average annual growth rate is x(1+x) 2=2x=5If you set it to x, it will be 1-x after the first price reduction

After the second price reduction, it is the original (1-x) (1-x) = (1-x) so (1-x) = 1 2

0007.The highest point to 5 m above the water with displacement s =

According to s=1 2 at2

So t=seconds.

8.Let the smaller number be x, 3x -25=(x+2) +x+4) 9.Set the unit digit to.

10.Solution: The price of each shirt should be reduced by X yuan.

40-x)(20+2x)=1200

800+80x-20x-2x2-1200=0x2-30x+200=0

x-10)(x-20)=0

x1=10 (rounded) x2=20

11.Solution: When the selling price is set at x yuan kg, you can make a profit of 200 yuan per day, then:

Meaning from the title: 40(3-x);

Simplification: 50 (x2) + 275x-378 = 0;

Solution: x1=rounded), x2=;

Therefore, when the price is positioned at Yuan kg, it can make a profit of 200 yuan per day, and the price is reduced by Yuan kg).

Set the foreign and domestic trade throughput of the previous year respectively x, y, then.

x+y=3300

1+10%)x+(1+20%)y=3760 solves x=2000, y=1300

Therefore, last year's domestic trade throughput was (1 + 20%) y = 1560, and this year is expected to increase by 10% to 1560 (1 + 10%) = 1716, if this year's foreign trade throughput is z, then (z + 1716) > = 4200, and z (z + 1716) > = 60%, by the two inequalities, z> = 2574. This year's foreign trade throughput is longer, with an increase of at least 2574-(1+10%), 2000=374 last year

I hope the landlord likes it and can my answer thank you.

The sum of your numbers is 16, and the number of tens is the sum of digits and hundreds, and the number of tens is 8

Let the hundred digits be x, and the single digit is 8 -x

100x + 80 + 8-x + 594 = 100(8-x) +80 + x

x =1 8-x =7

The original three-digit number was 187

The ten-digit number is the sum of the digit number and the hundred-digit number, so the ten-digit number accounts for half of the sum of the three digits. Since the sum of your digits is 16, the ten-digit number should be 8.

If the single digit is x, then the hundred digit is 8-x

So, the original number is 100 (8-x) + 80 + x

After the single digit is reversed from the hundred, the number is 100x+80+(8-x)According to the title, [100x+80+(8-x)]-100(8-x)+80+x]=594

Solve the equation and get x=7

So, the hundred digit is 1

The original number was 187

"The sum of your numbers is 16, and the number of tens is the sum of digits and hundreds", so the number of tens is 16 2=8, and the sum of single digits and hundreds of digits is 16-8=8

Solution: Let the hundred-digit number be x, then the single-digit number is (8-x).

100（8-x）+8x10+x-[100x+8x10+（8-x）]=594

800-100x+80+x-（100x+8x10+8-x）=594800-100x+80+x-100x-80-8+x=594-198x=594-800-80+80+8-198x=-198

x=18-x=8-1=7 Then the hundred digit is 1, and the single digit is 7

A: The original number is 187.

Let the single digit number be x, then by inverting the hundred digit with the single digit, then the new number is 594 larger than the original number, and we can know that the hundred digit is x-594 (100-1)=x-6, where the sum of the digits is 16 and the ten digits are 16-x-(x-6)=16-2x+6=22-2x

The ten-digit number is the sum of the digit number and the hundred-digit number, then.

22-2x=x-6+x gives a single digit x=7, a ten-digit x-6=1

The hundred digit is 22-2x=8

So this original number is 187

Single digit + tens + hundreds = 16 tens = single digits + hundreds and tens + tens = 16 tens of digits = 16 tens of digits = 8 Let the original hundreds of digits be x and the single digit number is 8-x The original number: 100x + 80 + 8-x

New number: 100(8-x) +80 + x100x + 80 + 8-x + 594 = 100(8-x) +80 + x

The solution is x = 1

8-x=7 is 187

187 Let the number be 100x+10y+z, then the system of equations is.

x+y+z=16

z+x=y100z+10y+x-(100x+10y+z)=594 The solution gives x=1, y=8, z=7

The tenth digit is 8, a8b-b8a=594 then a-b=6 because a+b=8 so a=7, b=1 the original number is 187

abca+b+c=16, b=a+c, thus obtaining b=8, a+c=8

100c+10b+a)-(100a+10b+c)=594, that is, 99(c-a)=594, i.e., c-a=6, so a=1, c=7

Original number 187

Let the corner edge be x-2

The other right-angled side is x

The hypotenuse is x+2

then there is (x-2) 2+x 2=(x+2) 2x 2-4x+4+x 2=x 2+4x+4x 2-8x=0

x(x-8)=0

x=8 so the three sides are 6, 8, 10

1.Solve 2 yuan once Some teachers and students of a school rent a car to conduct a social survey, there are 2 vehicles that can be rented, each type of vehicle can seat 8 people, each type of car B can sit 6 people, if only a few cars of type A are rented, then 4 seats are empty; If you only rent car B, there are 2 more cars than renting car A, and the seats are just full, how many teachers and students participated in this social survey?

2.There are two kinds of bonds, A and B, with an annual interest rate of 10% and 12% respectively, and the existing bonds are 400 yuan, and the profit is 45 yuan after a year.

3.Someone buys A and B for 24,000 yuan, and sells it when A** appreciates by 15 and B ****10, making a total profit of 1,350 yuan.

I hope my answer is helpful to you!!

Set up x kilometers of uphill road from A to B, and Y kilometers of flat road.

x/3+y/4+3/5=90/60=

3/3+y/4+x/5=102/60=

The solution is x=y=so the whole process is kilometers.

Set up x kilometers of uphill road from A to B, and Y kilometers of flat road.

x/3+y/4=54/60

x/5+y/4=42/60

The solution is x=2 3

y=5/8x+y=2/3+5/8=31/10=

Let the uphill slope be x hours of time difference! The difference is in the sloped section! The subsolution x of the column formula is equal to the level of the subsolution of the total distance of the column.

A binary equation for a kilometer is sufficient.

If Li's household water consumption is x cubic meters, then Zhang's household water consumption is 2 3x cubic meters, and the excess part will be charged according to Y yuan cubic meters.

According to Title 5*

5*Solution x=15 y=2

Therefore, the excess part will be charged at 2 yuan cubic meter.