Ask for advice on a math problem solution of a 2 dimensional equation .

Let the speed of A be x kilometers and B be y kilometers.

1/2x=（1+1/2）y

1/2x=1/2y+20-2

Solution x=54

y = 18 when A is 54 km/h, B is 18 km/h.

Let the speed of A be x kilometers and B be y kilometers.

y+1/2y=1/2x

20+1/2y-1/2x=2

This gives x=66

y=22A has a velocity of 66 km/h, B has a velocity of 22 km/h.

Let the speed of A and B be x and y respectively

x 54 kmh y 18 kmh.

Let the velocity of A be v and the velocity of B be u in km per hour.

20+ gives u=18v=54

solution, let the speed of A be x kilometers and the speed of B be y kilometers.

y×1+y×

20+y×x=54,y=18

A: A is traveling at a speed of 54 kilometers and B is traveling at a speed of 18 kilometers.

Set the original price to be $ x, and the profit to be $ y. Inspired by the comic topic, x y 360. Solution x 300, y 60. Hope it helps you!

There are 2 kinds:

With x cicadas and y spiders: 6x + 8y = 46

y=5y=2

Answer: There are two possibilities:1One cicada, five spiders. 2.Five cicadas, two spiders.

Set x sheets for the side of the canning box and Y sheets for the bottom surface.

16*x=43y/2

x+y=75

It's right.

It can be used to make x canned food boxes.

x/16+x/43=75

x = up to 874 canning boxes can be made.

Let the original number be 100000+a

From the meaning of the title, (10a+1)=300000+3aa=42857

Therefore, the original number is 142857

Let the last five digits be x

3(100000+x)=10x+1

x=42857

The original number 142857

Binary Linear Equations?

No, you don't. Thank you

Let the last 5 digits of the original six digits be x

100000+x）×3=10x+1

7x=299999

x=42875

The original six-digit number is 142875

For example, the speed of a bicycle is x kilometers per hour, and the speed of a motorcycle is y kilometers per hour.

The first equation is the velocity relation y=3x

The second is to walk in the opposite direction, the total distance they cover is 90km, the motorcycle walks 11-9 = 2 hours, and the bicycle walks 11-8 = 3 hours: 3x+2y=90

Substitute 3x+6x=90, 9x=90, x=10 and y=3x=30

So 30 km/h for motorcycles and 10 km/h for bicycles.

This question is a test of basic knowledge, and the thinking should be clear.

Solution: Let the bicycle speed be x and the motorcycle speed be y, according to the topic.

y=3x3x+2y=90

x=10y=30

A: The speed of the bicycle is 10 km/h and the speed of the motorcycle is 30 km/h.

First of all, you have a question, "Now you want to make a profit of 1,200 yuan".

Solution: Set the unit price of this batch of clothing to determine that x yuan is cheap, which is derived from the title:

x-50)*[800-20*(x-60) 1]=12000 Simplification: (x-50)*(2000-20x)=1200x 2-150x+5060=0

x=75±√ 565

When x=75- 565<60 is canceled.

So x=75+ 565 98 [the actual number is.]

The number of garments that should be entered: 800-20 * (98-60) = 40 (pieces) A: The unit price of this batch of clothing is determined to be 98 yuan cheaper? At this time, 40 garments should be entered.

If it is changed to "now you want to make a profit of 12,000 yuan".

The solution is as follows: Solution: Set the unit price of this batch of clothing sales to determine that x yuan is cheap, and the title is derived:

x-50)*[800-20*(x-60) 1]=12000 Simplification: (x-50)*(2000-20x)=1200x 2-150x+5600=0

x=70 or x=80

When x=70, the number of garments should be 800-20 * (70-60)=600 (pieces) When x=80, the number of garments should be 800-20 * (80-60) = 400 (pieces) The correct answer is as above, welcome to adopt!

Solution: Set a price increase of x yuan.

60-50+x)(800-20x)=12000 simplified (x-20)(x-10)=0

So x1 = 20 and x2 = 10

Because 50 (800-400) = 20,000<2400050 (800-200) = 30,000> 24,000 (rounded) 60 + 10 = 70

A: The unit price is 70 yuan, and 400 pieces should be entered.

If the sales unit price is x, the number of pieces sold is (800-20*(x-60)), and the profit of a single piece is x-50, so the total profit.

x-50)(800-20*(x-60))=(x-50)(2000-20x)=-20x^2+3000x-100,000=-20(x^2-150x+5000)=-20[(x-75)^2-625]

If the price is 75, the maximum profit is 20*625=12500, and as for the profit of 1200, calculate it yourself.

Set a price increase of x yuan.

60-50+x)(800-20x)>=1200, i.e., -2x, 2+60x+680>=0

If the solution is <=x<=, then there is a maximum value of -2*15 when x=-60 (2*(-2))=15 2+60*15+680=1520

Therefore, when the price is 50 + 15 = 75 yuan, there is a maximum profit of 1520 yuan, and 800-20 * 15 = 500 pieces, and when the price is 50 + 38 = 88 yuan, the profit is about 1200 yuan, and the price is 800-20 * 38 = 40 pieces of sweat, which is very economical in rent and freight, which is a bit too fake.

Solution: Set the price increase x yuan, then the selling price is 60 + x yuan, and the sales volume is 800-20x pieces (60 + x) (800-20x) - 50 (800-20x) = 1200, that is, (60 + x-50) (800-20x) = 1200 (10 + x) (40-x) = 60

400+30x-x^2=60

x^2-30x-340=0

1 Kiga (1 30 + 1 20) = 12 OK.

A(1-75%) 1 30) = days).

B (1-75%) 1 volt closure 20) = 5 (days) total 75% (1 30 + 1 20) = 9 (days) 9 + days) no.

9 + 5 = 14 (days) Yes.

Adjust the nails. The second.

1+40%)x*20%=2700/10

x=675/7

x is approximately equal to the judgment court.

The second question may not be correct.