Question

The function P(x)=5x+10 represents the total cost in dollars, P(x), of buying x paperback books from an online book club. 

(a) Identify the linear term and give a possible interpretation of its meaning.

(b) Identify the constant term and give a possible interpretation of its meaning.

(not multiple choice)

Answer 1

(A) The linear term is the term 5x. It indicates that each time x increases by 1, y or P(x) will increase by 5. Simply put, the 5 is the price per book. One book costs $5.

Note: 5 is the slope; slope = rise/run = 5/1

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(B) The constant term is the term without any variables attached to it. It's constant in that it never changes regardless of what x is. The constant term in this case is 10. This is the fixed cost that doesn't change no matter how many books are ordered. This fixed cost could be the shipping cost and other fees (assuming that shipping is a flat fee).

Note: 10 is the y intercept. This is where the line graph crosses the y axis.