because the y is opposite of each other in both equations you can cancel them out
3x=28
3x=14
next you add 3x to 3x, then 28 to 14 and get...
6x=42
next divide both sides by 6 and you get your answer for x...
x=7
now you must solve for y and you do this by substituting what you found for x in one equation it doesn't matter which because you'll get the same answer but you can check for both to make sure...
First add 11 and 4 because you need to know how many he had in total 11+4=15 then divide 15 by 3 and then you have you answer 15/3=5. There are 5 model cars in each pack.
