Final answer:
In the expression 5y+8, the number 5 is a coefficient, which multiplies the variable y, and the number 8 is a constant. The variable y represents a quantity that can change in value.
Step-by-step explanation:
In the expression 5y+8, the number 5 is a coefficient. A coefficient is a number that multiplies a variable, which in this case is y. The number 8 in the expression is known as a constant because it does not change in value; it remains the same no matter what value y has. Additionally, y is a variable, which means it can take on different values. Variables are often used to represent quantities that can change, depending on the situation. For example, if y represents the number of apples in a basket, the total number of apples can change, which would then change the value of the entire expression.