I don't like these computer choice thingies. It detracts from the math.
[tex]-x - 2y = 7[/tex]
[tex]5x - 6y = -3[/tex]
If we want to eliminate x we multiply the first equation by 5 then add it to the second:
[tex]-5x - 10y = 35[/tex]
[tex]5x - 6y + (-5x - 10y) = -3 + 35[/tex]
[tex]-16y = 32[/tex]
OK, that's how it's done. Reading through the choices, that's choice D.
