3x - y = 7 6x - y = 10 When solving this system of equations by elimination, which could be the resulting equation when a variable has been eliminated?

It depends on which variable is eliminated.

If you multiply the second equation by - 1 and eliminate the y:

3x - y = 7

-6x + y = - 10

-3x = - 3 or x = 1

If you multiply the first equation by - 2 and eliminate the x:

-6x + 2y = - 14

6x - y = 10

y = - 4