So the first thing you want to do is substitute. You want to plug in the equation for y in for the y value above.
So you would do 3x+4(x-1)=10. As you can see we took the bottom equation and put it in for the top equation. We did this so we only have x s and no y s.
Now you would solve. You would distribute first. You would get 3x+4x-4=10. Now combine like terms. 3+4 is 7 so you would get 7x-4=10.The next thing you want to do is get the 7x by itself so move the 4.You would get 7x=14. Now divided both sides by 7 because you want to get the x by itself.
You would get x=2. Now for the y value just plug it in for an equation above. The easier one would be y=x-1. y=(2)-1 will equal 1. You write your final answer in (x,y) style. Your final answer will then be (2,1)
All you need to do is 4,302 divided by 3. You would get 1434 pounds. I did this in my head. You can split it to get 4,200 divided by 3 + 102 divided by 3. You get 1400 + 34 which is 1434.