The multipliers of this system of equations have been determined to create opposite terms of the x-variable. 2 고 12(box- -5 > - 2x-Sy=-60 y=-9 => 2x+y==45 What is the value of y? 30
-15
15
30

Which of the following correctly justifies statement four of the two column proof? a. corresponding angles theorem b. transitive property of equality c. vertical angle theorem d. substitution property of equality