Answer
$C=\frac{-VL+SN}{N-L}$
Work Step by Step
$V=C - \frac{C-S}{L}N$
In solving for $C$, it must be isolated on one side.
Step 1. Add $\frac{C-S}{L}N$ on both sides:
$V+\frac{C-S}{L}N=C - \frac{C-S}{L}N +\frac{C-S}{L}N$
$V+\frac{C-S}{L}N=C$
Step 2. Subtract $V$ on both sides.
$V-V+\frac{C-S}{L}N=C-V$
$\frac{C-S}{L}N=C-V$
Step 3. Multiply the whole equation by $L$.
$(\frac{C-S}{L}N)(L)=(C-V)L$
$(C-S)N =(C-V)L$
Step 4. Expand the equations.
$(C-S)N$ = $CN-SN$
$(C-V)L$ = $CL-VL$
Step 5. Rewrite the equation from step 3.
$CN-SN$= $CL-VL$
Step 6. Subtract $CL$ from both sides.
$CN-SN-CL$= $CL-CL-VL$
$CN-SN-CL$= $-VL$
Step 7. Add $SN$ to both sides.
$CN-SN+SN-CL$= $-VL+SN$
$CN-CL=-VL+SN$
Step 8. Use the distributive property to convert the two occurrences of $C$ into one.
$C(N-L)=-VL+SN$
Step 9. Divide the whole equation by $N-L$.
$\frac{C(N-L)}{N-L}=\frac{-VL+SN}{N-L}$
$C=\frac{-VL+SN}{N-L}$