# Thread: 6x+3=2x-7...how to find x?

1. ## 6x+3=2x-7...how to find x?

How can you find x in this equation? and if you can please answer this problem--and explain why.

Two hikers left at 9:00. The other hiked south with a speed of 4km/h while the other hiked north at 3km/h.How long can they stay connected if their walkie-talkies've got a max. range of 10km? (Sorry for the bad english, the problem was written in french).

2. Hello Julian.Ignacio!

Originally Posted by Julian.Ignacio
How can you find x in this equation? and if you can please answer this problem--and explain why.

6x+3=2x-7

6x + 3 +7 = 2x - 7 + 7

6x + 10 = 2x + 0

6x +10 - 6x = 2x - 6x

10 = -4x

divide by -4

- (10/4) = x

-10/4 is equal to -5/2

Originally Posted by Julian.Ignacio
Two hikers left at 9:00. The other hiked south with a speed of 4km/h while the other hiked north at 3km/h.How long can they stay connected if their walkie-talkies've got a max. range of 10km? (Sorry for the bad english, the problem was written in french).
I give you a hint: because one hiker goes north 3km/h, the other goes south 4km/h, it is like there is only one hiker traveling into one direction with (3+4)km/h = 7km/h.
Then you want to know how long it takes to reach the 10km mark.

So you need to solve

7 (km/hours) * x (hours) = 10 (km)

Yours
Rapha

3. Originally Posted by Julian.Ignacio
How can you find x in this equation? and if you can please...explain why.
To learn the "why" and "how", try here.

4. @Stapel: Haha thanks! I chose math-bilingual so my math is in french; I really needed a theory in english!!! THANK YOU!!!!!!!!!