Answer:
Step-by-step explanation:
Letters are variables and those variable can store a number
Ex: x=5 y=2
evaluate : 3x+2y
we know that x is 5, so we know that 3x would be 15
we know that y is 2, so we know that 2x would be 4
then it says to add 3x and 2y, we would add 15 and 4 to get 19
(This is a very simple example, when you get older, the expression would be much more confusing.
