Respuesta :

mother0ginger
they define the same line because all of the numbers in the equation are tripled (properties of equality). 
kaivalyashenoy
x+y=-2
multiply the whole equation with 3
you will get 3x+3y=-6
x+y=-2
and 3x+3y=-6 are equivalent
the values of x and y is same in both the equations
so they define the same line.