( 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.