I am trying to get Excel to find a solution to a 10
variable system of equations by supplying a range for one
variable. I work for a steel company and I am trying to
set up a spreadsheet calculating the cheapest option for
galvanizing steel at two different places with four
different size tanks and six different freight charges. I
have all 10 equations set up, but can't figure out how to
enter the variables in solver. I also need it to select a
minimun value for the range of numbers I give it. Two
variables in the below equations happen to be zero for
this particular problem:

x7 = 0
x10 = 0

x1 + x2 + x3 + x4 = 666.41

x5 + x6 + x7 = x8 + x9 + x10 = 666.41

x5 + x6 + x7 - x8 - x9 - x10 = 0

x1 + x2 - x3 - x4 = 0

x5 + x8 = 590.31

x6 + x9 = 76.1

x7 + x10 = 0

x1 + x2 - x5 -x6 - x7 = 0

x3 + x4 - x8 - x9 - x10 = 0

150x1 + 150x2 + 150x3 + 150x4 + 61.05x5 + 87.45x6 + 0x7 +
22.5x8 + 31.05x9 + 0x10 = ?

* To find a solution, I want the minimum value of '?' when
x1 = 0 to 666 in increments of 1.

Can anybody help me? I would really appreciate it.

Thanks,

Todd