Which properties justify the steps taken to solve the system?

{2x−4y=−63x+2y=−1

Drag and drop the answers into the boxes to match each step.

{6x−12y=−186x+4y=−2

−16y=−16

y=1

2x−4(1)=−6

2x−4=−6

2x=−2

x=−1
these are the options given:
Action property of equality
Division action of equality
Multiplication of equality
associative property of addition
property of equality
simplify
Substitution Property of equality

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)