Solving Multi Step Equations

[brazil820]

Hi everyone, we are new to this forum and hoping someone can help us understand this problem. here is a screenshot of the actual problem:
https://gyazo.com/20a0de31612e5635f791bc7cde9a9251

This is how it's solved but we are not understanding how they got a -4x on the left side:
https://gyazo.com/6f834a49aea6b8919636a4ca94e1ea40

Could someone please explain?

Thank you!

 

[ksdhart2]

The -4x on the left side comes from subtracting 3x. To use an analogy which might further your understanding, let's say that subtracting x from something is the equivalent of owing your friend a dollar. So the -x you started with represents owing your friend one dollar. Now, you subtracted 3x, or 3 times x. That can be expressed by -3x. How many dollars does that expression represent owing your friend? If you initially owed your friend one dollar, and now you owe him an additional (how many?) dollars, then how many total dollars do you owe him? How does that relate to the given answer of the problem?