Let's breakdown the process to determine what among the 5 procedures was being applied to simplify the equations.
A.) From 6x + 9 = 4x - 3 to 2x + 9 = -3
By applying the inverse property of addition, we get,


Thus, for 6x + 9 = 4x - 3 to become 2x + 9 = -3, we add -4x to both sides.
Number 4 is the procedure being applied.
B.) From -4(5x - 7) = -18 to 5x - 7 = 4.5
By applying the inverse property of multiplication, we get,


Thus, for -4(5x -7) = -18 to become 5x - 7 = 4.5, we multiply both sides by -1/4.
Number 1 is the procedure being applied.
C.) From 8 - 10x = 7 + 5x to 4 - 10x = 3 + 5x
We add -4 to both sides,


Thus, Number 5 is the procedure that must be applied.
D.) From (-5/4)x = 4 to 5x = -16
Applying the inverse property of multiplication, we get


Thus, for (-5/4)x = 4 to become 5x = -16, we multiply both sides by -4.
Thus, Number 2 is the procedure the must be applied.
E.) From 12x + 4 = 20x + 24 to 3x + 1 = 5x + 6
Let's apply procedure Number 3 if it is the right one to be applied. We get,



Thus, Number 3 is the procedure that must be applied.