Which of the following represents a nonlinear function? Show work pls

a.

y = –9x

b.

y = x

c.

y = 4x^2

d.

y = 8x + 10

You’re ordering more thread for blue jeans co. you usually purchase from ted’s threads, which sells 12 thread spools for $27. you recently received a notice from wade's wares that says you can buy thread from them for $2.30 each for the first 2 dozen and $2 a spool thereafter. you need to order 5 dozen spools. what percentage can you save by going with wade’s wares?