# Working out total cost

• Oct 9th 2007, 06:33 PM
JTE
Working out total cost
If someone could give me the breakdown of how you get the final answer in this equation I will love you forever :D Just need to know how you get 57 so I can apply the same theory to other problems!

I have done it on paint because I haven't got a clue how to write cubed and squared on a keyboard :D

http://img116.imageshack.us/img116/1...gggggggzq6.png

Thanks very much
• Oct 9th 2007, 06:47 PM
JTE
With C being Cost...
• Oct 9th 2007, 07:18 PM
Jhevon
Quote:

Originally Posted by JTE
If someone could give me the breakdown of how you get the final answer in this equation I will love you forever :D Just need to know how you get 57 so I can apply the same theory to other problems!

I have done it on paint because I haven't got a clue how to write cubed and squared on a keyboard :D

http://img116.imageshack.us/img116/1...gggggggzq6.png

Thanks very much

just work it out piece by piece.

\$\displaystyle 3^3 = 27\$

\$\displaystyle 10(3)^2 = 10(9) = 90\$

\$\displaystyle 40(3) = 120\$

thus, \$\displaystyle c(3) = 3^3 - 10(3)^2 + 40(3) = 27 - 90 + 120 = 57\$