I've the data corresponding to two points on the line Ff = a z + b, which meet the following condition :
0.1 a + b = 0
0.2 a + b = 0.2 (Lb + 0.2 Hg) G/L
The following code is used to find the coefficients a and b:
In[165]:= data = {{0.1, 0}, {0.2, 0.2 (Lb + 0.2 Hg) G/L }};
a z + b /.
Solve[a data[[1, 1]] + b == data[[1, 2]] &&
a data[[2, 1]] + b == data[[2, 2]], {a, b}] // Simplify
Ff = 2 (z - 0.1) (Lb + 0.2 Hg) G/L
% - %% // Simplify
Out[166]= {0. + (0.4 G (Hg (-0.1 + 1. z) + Lb (-0.5 + 5. z)))/L}
Out[167]= (2 G (0.2 Hg + Lb) (-0.1 + z))/L
Out[168]= {0. + (5.55112*10^-17 G Lb)/L}
Where, the equation Ff = 2 (z - 0.1) (Lb + 0.2 Hg) G/L is the solution calculated by hand. As you can see, it's not consistent with the result given by Wolfram.
Any hints for this problem will be appreciated.
Regards, Zhao