Step-by-step explanation:
I don't know which answer option is which letter.
the right answer is the one top right with
-6x - 15y = -135
why ?
well, the second equation is unchanged to the original.
and the first equation is just the original first equation that was multiplied on BOTH, the left and the right side by the same factor : -3
therefore, its information and validity is unchanged compared to the original.
and so, this combination has the same solution as the original.
