How do you solve # y=x+3# and #y=2x# using substitution?
a quick mental check in
Substitution in a system means that you write a variable in term of the other(s), and then replace every occurrence of that varable in the other equations.
It's easier done than said! Let's take a look at your system:
Both equations give us an explicit representation of
This is an equation involving
Once we find one variable, we deduce the other using it's explicit representation: we knew that
PS, note that this was a special case, since both equations were an explicit representation for
By guessing what is the value of
We have to find the value of
We have to guess the value of
Let's make the value of
That will become:
This can't be right because the
Let's go up by one number: 3
The answer is 6.
Hope this helps!!