Final answer:
The correct symbolic expression for 'y is 9 less than 5 times a number n' is y = 5n - 9, represented by option A.
Step-by-step explanation:
The symbolic expression for "y is 9 less than 5 times a number n" is mathematically represented by the equation y = 5n - 9. This is because we first multiply the number n by 5 (which gives us 5 times n, or 5n) and then subtract 9 from the result. Therefore, the correct option from the given choices is A) y = 5n - 9.