I =T-C-S
1) Solving the formula for I, we'll have the Installation Cost. Let's do it using some algebraic manipulation:
2) Subtracting I from both Sides we have, right after that subtract T from both sides
[tex]\begin{gathered} T=C+S+I \\ T-I=C+S \\ -I=C+S-T \\ I=T-C-S \end{gathered}[/tex]3) Note that to get I, we had to divide the whole equation by -1.
Hence, the answer is I =T-C-S
