Step by step
The question
Question: solve 3(x + 4) = 27.
Let's find x.
Is x alone now?
Not yet: 3(x + 4) means 3 times x.
How do we remove it?
1 Remove the 3
The 3 multiplies the whole bracket.
Easy way: remove the 3 first.
Then we do not have to open the bracket.
To remove times 3, we divide by 3.
We do it on both sides.
Why both sides?
The = sign means both sides are the same amount.
If we change only one side, they are not the same any more.
3 divided by 3 is 1.
So just the bracket is left.
27 divided by 3 is 9.
Now we have x + 4 = 9.
We don't need the bracket any more.
So after step 1: we divided by 3, and now we have x + 4 = 9.
Is x alone now?
Not yet: + 4 is still with x.
2 Remove the + 4
We want x by itself.
The + 4 is in the way.
To remove + 4, we take away 4.
We do it on both sides, so they stay equal.
+ 4 and − 4 cancel each other.
They make zero.
9 − 4 = 5.
So x = 5!
3 Check
Let's check: put 5 in place of x.
We get 27, the same as the right side.
So x = 5 is right!
4 Type it in
The answer box takes 5 characters.
5 has 1.
It fits.
We type 5.
Let's look back.
First: remove the 3.
Then: remove the + 4.
Then: check.
Last: type it in.