Answer:
(A) the subtraction property of equality
Step-by-step explanation:
Given
The steps in the question
Require
Justify step 2 to 3
Write out step 2:
[tex]-4x+9 = 2x+10[/tex]
Apply subtraction property by subtracting 2x from both sides
[tex]-4x-2x+9 = 2x-2x+10[/tex]
[tex]-6x+9 = 10[/tex]
Notice that the above equation is represented in step 3.
Hence, option A answers the question.