Question 1025758
let S equal the cost of the skateboard.


they didn't give you this variable, so select it yourself.


you could use any variable name, but S is pretty good since it's the first letter of skateboard and it's not being used anywhere else in the equation.


you are given that H equal the cost of one helmet.


this means that the cost of two helmets is equal to 2H.


you are given that the total cost equals D.


your equation is S + 2H = D


this means thsat the cost of one skateboard and two helmets is equal to D dollars.


subtract 2H from both sides of the equation to get:


S = D - 2H


since S = cost of the skateboard, then that's your answer.


the cost of the skateboard is represented by D - 2H.