( 1)
The first scheme:
y=30×8+(x-8)×5=5x+200
The second plan:
y = 30×8×0.9+5×x×0.9 = 4.5x+2 16
(2)
Let 5x+200=4.5x+2 16.
Pack up, take it
0.5x= 16
x=32
When buying 32 pencil cases, the two schemes pay the same fee.