For this case we have to:
x: Be the variable that represents the unknown number
Then, the product of 9 and a number is represented as:
[tex]9 * x[/tex]
If the product is reduced 7 units we have to:
[tex]9x-7[/tex]
Finally the expression is:
[tex]9x-7[/tex]
ANswer:
[tex]9x-7[/tex]
