(40 points, wiva? ) which properties justify the steps taken to solve the system? {2x−4y=−6 {3x+2y=−1 {6x−12y=−18 6x+4y=−2 −16y=−16 y=1 2x−4(1)=−6 2x−4=−6 2x=−2 x=−1