15 unary equation problems with solutions. Fast!!!! Worry!!!

Method 1:

Solution: Arrive when the original plan is x

Equations can be listed by the title:

60x = solution: x = 12

60x = 720 (km).

Method 2: Solution: When Y is done later:

Equations can be listed by the title:

60 (solution: y=.)

60 (km).

Method 3: Solution: After assuming that you have traveled z kilometers.

Equations can be listed by the title:

60*Solution: z=450

60 (km).

A: A and B are 720 kilometers apart.

This is the general fraction, and then go to the denominator, have you ever learned the general fraction?? Do you know how to find the common denominator? And then went to the denominator to learn??

Let the purchase price be x[(100%+50%)x+40]x50%=x+15

Solution x=20

Therefore, the purchase price of each top is 20 yuan.

a b c d e f g h

The above line segment represents the total distance, and the starting point is 25 people transported by car, transported to point E, and returned to point B. At this point, the rest of the people walked exactly to point B, transported 25 of them to point F, and then returned to point C... ab=bc=cd=ef=fg=gh

It takes x hours to set up a person to walk the AB section. AB is 5x long, DE is 33-30x long

In time x, the car goes 55x, and then there is a geometric relationship to know that the car goes 3*5x+33-30x+33-30x+2*5x

55x=3*5x+33-30x+33-30x+2*5x

The solution is x=11 15

Total time 3x+(33-15x) 55=

The people are divided into four groups, and when the car sends one of the groups, the other people walk, and then the car returns to pick up the car, and it takes a full trip and three round trips to finish.

Let the first full journey time be T1, and the three round-trips are T2, T3, and T4, then T1=33, 55, T2=33-5T1, T3=33-5(T1+2T2), T4=33-5(T1+2T2+2T3).

The total time t = t1 + t2 + t3 + t3 can be calculated as time t, if the time t result is multiplied by 5 and is greater than 33, then it means that the time for the person to go directly to the whole distance is the shortest, then the shortest time at this time t = 33 5

It can be seen as a catch-up problem similar to that of a circular runway.

Walking distance + car trip = total distance * 2

1) Pick up 25 people to their destination first, and then return by car.

2) The car returns to meet the rest of the people, picks up 25 people again to the destination, and then returns again (3) The car returns a second time to meet the rest of the people, picks up and drops off 25 people again to the destination, and then returns again.

4) The car meets the remaining 22 people on the third return and then takes them to their destination.

The total time is equal to the sum of the time of these four transfers, and you only need to find the time of each stage of the transfer once.

Assuming that the original price of each set of such cosmetics is x yuan, the solution is: x = 150 (yuan).

Purchase price = (yuan).

A: The original price of each set of these cosmetics was 150 yuan. The purchase price is 110 yuan.

Set price x

The solution is x=150

Set the original price y20*150-30y=300

The solution is y=90 yuan.

A: The original price of each set of such cosmetics was 150 yuan, and the purchase price was 90 yuan.

Set the original price as x, then there is the first plan to earn 600 yuan more than the second plan, which can be set and calculated to get x 150 yuan. If the purchase price is y, then there is, and it is calculated as y 110

The purchase price is 90, and the original price of 150 yuan should be the correct answer.

(1) If the price of each piece of children's clothing should be reduced by X yuan, and the profit obtained is Y yuan, then there is.

y=(20+8*x 4)*(40-x)=2(-x 2+30x+400) (where 0 makes y=1200, the solution is x=20 (where x=10 is not in line with the topic, and is discarded) (2) from y=2(-x 2+30x+400)=2[-(x-15) 2+625] know that when x=15, there is the greatest benefit.

That is, the price of each piece should be reduced by 15 yuan to obtain the maximum benefit.

But by the title, 15 should be a multiple of 4, so 16 can be taken

Set the price reduction x yuan (40-x)(20 8 x 4) 1200 to solve it yourself.

Original = [(a-2)(a+2) (a-2) +1 (a+2)] a(a-2) 2

The result is a(a+3) 2=a +3a 2 because a is the root of the equation x 2 + 3x + 1 = 0.

So a +3a + 1 = 0

So a +3a = -1

So the original formula = -1 2