1. Oct 3, 2006

### physicsgal

1) "find the vertex algebraically"

y= -x^2 - 3
y = (x - 3)(x+1)??
(the -x is throwing me off)

~Amy

8. Oct 3, 2006

they should charge $1.05 according to the revenue function. Is there more information to this question? 9. Oct 3, 2006 ### physicsgal that's all the info to the question. but the answer sounds a bit iffy. thanks, but i dunno. if you calculate$1.50 for c into the original formula:
R = -40c^2 + 84c
the revenue = 36

unless im calculating that wrong

~Amy

10. Oct 3, 2006

Its $1.05 not$1.50.

11. Oct 3, 2006

### physicsgal

k, with $1.05 i calculated the revenue to be$1852.2

with the original $8.5 i calculated it to be$116314

~Amy

12. Oct 3, 2006

Are you sure? In $$R(c) = -40c^2 + 84c$$, the -40 is outside of the squared expression. So you square c first, then multiply it by -40 and add it to 84c.

$$-40c^2$$ does not equal $$(-40c)^{2}$$

Last edited: Oct 3, 2006
13. Oct 3, 2006

### physicsgal

k, sorry for the hassle, looks like you are right

thanks again!

~Amy