Because if there is no more supplies for the sale, the sale can't apply to nothing!
N= -1
then 10- 6.2x-1=16.2
Plug y=2x+1 into <span>x+2y=17, we have:
x+ 2(2x+1)= 17
</span>⇒ x+ 2*2x+ 2*1= 17 (distributive property)
⇒ x+ 4x+ 2= 17
⇒ 5x= 17-2
⇒ 5x= 15
⇒ x= 15/5
⇒ x= 3
<span>
y= 2x+1= 2*3+1= 7
Final answer: x= 3, y= 7~</span>