Joel and Kevin are each putting money in a savings account to buy a new bicycle. The amount, in dollars, in Joel’s savings account, x weeks after the start of the year, is modeled by function j. The amount of money in Kevin’s account, at the same time, is modeled by function k. j(x) = 25 + 3x
k(x) = 15 + 2x

Which function correctly represents how much more money, in dollars, is in Joel’s account than in Kevin’s account x weeks after the start of the year?

A.
(j − k)(x) = 40 + 5x
B.
(j − k)(x) = 40 + x
C.
(j − k)(x) = 10 + 5x
D.
(j − k)(x) = 10 + x

Given:

The amount of money in Joel’s account is:

The amount of money in Kevin’s account is:

To find:

The function that correctly represents how much more money, in dollars, is in Joel’s account than in Kevin’s account x weeks after the start of the year.

Solution:

We need to find the difference between the function j(x) and function k(x).

Therefore, the correct option is D.

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.