Question

Question below

Answer 1

What is the easiest way to rearrange equations? I finally found an easy way to solve equations
For instance
3x+y=12
That's the easier way
My book would go like
3x+y-y=12
Which would confuse me with the equations next to each other *+y-y*
Putting the minus or plus underneath it helped me to understand it better. But rearranging equations confuses me when I have to reverse the sign.