I agree, your teacher should have shown this to you.
I will work a similar problem, to show the basic ideas.
There are two things to keep in mind.
1) Keep both sides of the equation EQUAL. So if you add 5 to one side, you add 5 to the other side.
2) Combine like terms. Add all of the x's together. Add all of the y's together. Add all of the numbers together.
For example
5x = 16 + x
"x" is really a short way of saying "1x".
It would be good if we could get all of the x's together, but we have to keep both sides of the equation equal.
Let's see what happens if we subtract x from both sides.
5x - 1x = 16 + 1x - 1x
5x - 1x simplifies to 4x
16 + 1x - 1x simplifies to 16 + 0x. If I give you a piece of candy, then take it away, how many pieces of candy do you have? 0
Any number times 0 equals 0.
Therefore, we can simplify this equation to
4x = 16 + 0x
4x = 16 + 0
4x = 16
Now, we need to solve for x, so lets divide by 4. Don't forget to divide BOTH sides....
4x/4 = 16/4
x = 4
Now, we can check to make sure we did it right.
5x = 16 + x
5(4) = 16 + 4
20 = 16 + 4
20 = 20
We got the right answer!
Now, can you use these ideas in your problems?
