# Check cell for both methods Method 1 preferred Solver with no Target cell

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```					Are you using Solver correctly?

x            f(x)               Check
2          -10         Not Solved

Formula in B8: =x^2-x-12

These two methods are equivalent!

The top model uses a Target Cell, the
bottom one uses a Constraint with no Target
Cell.

When you use a Target Cell set to Value,
Solve actually treats it as a Constraint.

That is why the Precision setting will affect
both methods. From "Solver User Guide":
The [value of Precision] determines how
closely the calculated values of the
constraint left hand sides must match the
right hand sides in order for the constraint to
be satisfied.

a2d5c75f-01b8-4272-a578-df18987d5c23.xls              Prepared by Bernard V Liengme   7/21/2012
A          B         C         D            E             F               G      H           I            J          K    L
1
2   Are you using Solver correctly? B                                                  Solve the system of equations
3
4                                                                                      2 x  4 y  5z  30
5   Example: simultaneous equations                                                    5 x  2 y  3z  23
6   A problem with more than one 'target cell'                                         9 x  y  6 z  12
7
8             Variables                                                                Method 1 (preferred)
Initially, 'guesses' for x, y and z         Solver with no Target cell
9      x          y         z
Changing A10:C10
10      1          1         1                                                          Constaint: G13:G16 = 0
11                                                                                      Precision set to 1 × 10-10
12            Coefficients                    Constants                     Targets     Gives correctly x=1, y=-3, z=4
13      x          y         z
14      2          4         -5                    -30                             31
Method 2
15      5         -2         3                      23                            -17
Solver with Target cell G18
16      -9         1         6                      12                            -14   Changing A10:C10
17                                                                                      No Constraints
18                                                                            62        Precision set to 1 × 10-10
19     Formula in G13 (copied down to G16)                                Not Solved    Gives x=0.9964, y=-3.0041, z=3.9953
20     =SUMPRODUCT(\$A\$10:\$C\$10,A14:C14)-E14                                             To get closer answers needs Constraint
21                                                                                      A10:C10 = integer
22
23          In G18 =ABS(G14)+ABS(G15)+ABS(G16)
24          Target cell for second method                                                                These results obtained
Check cell for both methods                                                                   with x = y = z = 1 as
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initial guesses
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Systems of Equations (Simultaneous Equations) are better solved with
31                            matrix algebra but I wanted a simple Solver example

a2d5c75f-01b8-4272-a578-df18987d5c23.xls                 Prepared by Bernard V Liengme                                                7/21/2012]
A         B                    D            E          F
Cmatrix algebra but I wanted a simple Solver example
G          H   I   J   K   L
32

a2d5c75f-01b8-4272-a578-df18987d5c23.xls               Prepared by Bernard V Liengme                       7/21/2012]

```
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