Q:

How to solve a equation task

I have found a equation task that is:
y=0,5x+2,5
y=3x-1

The answer and its process is:
0,5x+2,5 = 3x-1 (+1)
0,5x+3,5 = 3x (-0,5x)
3,5 = 2,5x
x = 3,5/2,5 = 1,4
and y will be 3*1,4 -1 = 3,2

There is one thing that I don't understand that is.
0,5x+3,5 = 3x (-0,5x)
3,5 = 2,5x

How can it be 2,5x? Should it be -x or something?  
A concrete explaination would be great.  
Thanks!

A:

Lets just focus on that step: $3x - 0.5x = (3-0.5)x = 2.5x$. Does that clear it up for you?

