Sally is packing balls for shipping. Each ball is packed in a box shaped as a cube with 6 inches on each side. The individually packed balls are placed in a larger shipping box
which is 5 feet on each side. How many balls can be packed into the larger shipping box?

The answer is “faster”.

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.