Let y represent jarons age in years. if dawn were 5 years older, she would be jarons age. which expression represents dawns age?

This is a simple subtraction question, 
y is a variable, so Jaron could be any age and still be 5 years older than dawn. 

lets say Jaron is 20, since he is five years older, we can subtract 5 from 20 and get 15

so
y = 20 
d = 15

d = dawn's age

The value of an expression, is a variable or a constant of any number or other mathematical object assigned to it. the value of a mathematical expression is the result of the computation described by this expression when the variables & constants in it are assigned values .

ur welcome!