Step by step
The question
Question: find g(3) for g(x) = x + 7.
g(x) = x + 7
g(x) is read "g of x".
It is a rule, called a function.
A number goes in for x.
The rule gives one answer out.
g(x) = "g of x"
x goes in → an answer comes out
1 Put the number in
g(3) means: put 3 in place of every x.
Every x becomes 3.
g(3) = 3 + 7
2 Add
3 plus 7 is 10.
g(3) = 10
So g(3) = 10.
Let's look back.
First: put the number in.
Last: add.
Answer
g(3) = 10