Question

Решите уровнение: -4 × (3-X) = 2 × X + 7 Задача: из пункта А в пункт В выехал велосипедист со скоростью 12 км/ч. После того, как велосипедист проехал 3 км, из пункта А со скоростью 4 км/ч вышел пешеход, который пришёл в пункт В на 5/4 ч позже велосипедиста. Найдите расстояние между пунктами. ○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○●○● Зарание спасибо

Answer 1

-4(3-х)=2х+7
-12+4х=2х+7
4х-2х=7+12
2х=19
х=19:2
х=9,5

х - расстояние между пунктами
3:12=1/4 (ч) ехал велосипедист до выхода пешехода
х/4 - время движения пешехода
х/12 - время движения велосипедиста
5/4-1/4=4/4=1 (ч) разность времени движения
х/4-х/12=1  (умножим на 12)
3х-х=12
2х=12
х=12:2
х=6 (км)
Ответ: между пунктами 6 км

Answer 2

Equation Solution:

To solve the equation -4 × (3-X) = 2 × X + 7, we can follow these steps:

1. Distribute the -4 on the left side of the equation: -12 + 4X = 2X + 7. 2. Move all the terms with X to one side and the constant terms to the other side: 4X - 2X = 7 + 12. 3. Simplify: 2X = 19. 4. Divide both sides of the equation by 2 to solve for X: X = 19/2.

Therefore, the solution to the equation is X = 19/2.

Distance between Points A and B:

To find the distance between points A and B, we need to consider the information given in the problem.

1. The cyclist starts from point A and travels at a speed of 12 km/h. 2. After the cyclist has traveled 3 km, a pedestrian starts from point A and walks at a speed of 4 km/h. 3. The pedestrian arrives at point B 5/4 hours later than the cyclist.

Let's calculate the time it takes for the cyclist to reach point B:

- Time = Distance / Speed - Time = 3 km / 12 km/h = 1/4 hour

Since the pedestrian arrives at point B 5/4 hours later than the cyclist, the total time for the pedestrian to reach point B is:

- Total Time = Time taken by the cyclist + Delay - Total Time = 1/4 hour + 5/4 hour = 6/4 hour = 3/2 hour

Now, let's calculate the distance between points A and B using the formula:

- Distance = Speed × Time - Distance = 4 km/h × 3/2 hour = 6 km

Therefore, the distance between points A and B is 6 km.