The $ is used for absolut referencing. For e.g lets take your formula
=G8*($A$14*2)*100
suppose you enter this formula in cell B2, now simply copy this formula one
cell to the right (C2) by and one cell down (B3).
C2: =H8*($A$14*2)*100
B3: =G9*($A$14*2)*100
So you see that The original G8 has changed, whereas $A$1 remains the same
in both the new formulae because of the dollar signs.
Mangesh