Question

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?

Answer 1

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