Combine like terms. So that means combine the X's and combine the regular numbers.
- add 2x to 8x
- combine +15 -5
- then add 11 to that
- once you're done, find X by dividing 10x by whatever you have after the = sign
7 pens and 20 pencils because 28 divided by 4 = 7 and 80 divided by 4 = 20
A because one input can have only one output
