Yea, -7 is the correct answer
Answer:
49
Step-by-step explanation:
Answer: -7cos(x)
Step-by-step explanation:
d/dx (f(x))= -7cos(x)
Y = 12x......y = 12(4).....y = 48.....so she pays $ 48 for the old brand when buying 4 boxes
y = 8x...y = 8(4)......y = 32...so she pays $ 32 for the brand she changed to, when buying 4 boxes
so the super saving brand would save her (48 - 32) = $ 16 per month
A, C, and D. Hope this helps!
