which statements are true about the expression y + 9? choose all that apply. the letter y is a variable. the…

Explanation:

Step1: Define variable

A variable is a symbol that can take different values. Here, $y$ is a symbol whose value can vary, so "The letter $y$ is a variable" is true.

Step2: Define constant

A constant has a fixed value. The number 9 has a fixed value, so "The number 9 is a constant" is true. Also, 9 is a single - valued entity in the expression, so "The number 9 is a term" is true. And $y$ is also a term in the expression. A constant is not a variable, so "The letter $y$ is a constant" and "The number 9 is a variable" are false.

Answer:

The letter $y$ is a variable., The letter $y$ is a term., The number 9 is a constant., The number 9 is a term.