# How do you solve # y=x+3# and #y=2x# using substitution?

##### 3 Answers

#### Explanation:

substitute

a quick mental check in

#### Explanation:

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

#### Explanation:

We have to find the value of

We have to guess the value of

Let's make the value of

That will become:

*2.
Simplify; #y# = 5 and #y#= 4
This can't be right because the #y#'s value is different.
Let's go up by one number: 3
That is:
#y# = 3 + 3 and #y# = 2*3

Which is:

**The answer is 6.**

Hope this helps!!