I think you type the wrong equation but I can guess that v is x or maybe a space
but if v = space. The answer will be false.
so I'll put x instead of v
[tex]5x - 7x - 9 = - 2x + 5x - 9 \\ (5x - 7x) - 9 = ( - 2x + 5x) - 9 \\ - 2x - 9 = 3x - 9 \\ 5x = 9 - 9 \\ 5x = 0 \\ x =0[/tex]
The answer is 0
