Step by step
The question
Question: solve 0.25(x − 4) = 1.5.
1 Remove the decimals
Decimals are hard to work with.
Let's get rid of them.
We multiply every part by 100.
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.
Times 100 moves the point 2 places to the right.
100 × 0.25(x − 4) = 25(x − 4).
100 × 1.5 = 150.
Write the answers.
No more decimals!
2 Remove the 25
The 25 multiplies the whole bracket.
Easy way: remove the 25 first.
To remove times 25, we divide by 25.
We do it on both sides, so they stay equal.
25 divided by 25 is 1.
So just the bracket is left.
150 divided by 25 is 6.
Now we have x − 4 = 6.
We don't need the bracket any more.
3 Remove the − 4
We want x by itself.
The − 4 is in the way.
To remove − 4, we add 4.
We do it on both sides, so they stay equal.
− 4 and + 4 make zero.
Cross them out.
6 + 4 = 10.
So x = 10!
4 Check
Let's check: put 10 in place of x.
We get 1.5, the same as the right side.
So x = 10 is right!
Let's look back.
First: remove the decimals.
Then: remove the 25.
Then: remove the − 4.
Last: check.