Question

The value of a baseball​ player's rookie card began to increase once the player retired. When he retired in 1998 his card was worth ​$8.39. The value has increased by ​$2.16 each year since then. Express the relationship relating the value of the card y in dollars and the number of years x the player has been in retirement with an equation. Is the relationship between x and y​ proportional? What was the value of the card in 2009​?

Answer 1

The equation would be 8.39 + 2.16x = y;
To get x you would want to subtract 2009 by 1998. You get 11 (years). So 8.39 + 2.16 • 11 = $32.15.

Answer 2

8.39+2.16•x=y

x=years after retirement
y=final value of the card

no it is not proportional

2009 is 11 years after the players retirement, sub 11 for x