Answer:12x - 14y cubic yardsStep-by-step explanation:a keyword in this is... differenceit also asks you to compare the first truck to the second truck not the second to the firstx = the amount of mulch the first truck can delivery = the amount of mulch the second truck can deliverthe first truck takes 12 trips so 12 trips multiplied by x (the amount of mulch the first truck can deliver) is 12x because it doesn't give us xthe second truck takes 14 trips so 14 trips multiplied by y (the amount of mulch the second truck can deliver) is 14y because it doesn't give us yThe question asks for the difference between the total number of cubic yards that the first truck carries through their 12 trips and the total number of cubic yards that the second truck carries through their 14 trips. This gives us, 12x - 14y cubic yardshopefully, this makes sense :)