Step by step
The question
Question: find the value of 5a − 1 when a = 3.
5a − 1
a = 3
1 Put the numbers in
We put 3 in place of a.
5a means 5 times a.
So we write a times sign.
= 5 × 3 − 1
5a = 5 × a
2 Times and divide
Times comes before minus.
Order: ( ) → x² √ → × ÷ → + −
5 times 3 is 15.
= 15 − 1
3 Plus and minus
15 minus 1 is 14.
= 14
So 5a − 1 is 14 when a = 3.
Let's look back.
First: put the numbers in.
Then: times and divide.
Last: plus and minus.
Answer
= 14