Here we have an equation in one variable "w"
What we need to is getting rid of (-1/25) that is multiplied by "w"
right?
so we need to multiply both sides by "-25", so we get:
[tex]- \frac{w}{25} *-25=25*-25\\~\\w=-25^2=-625[/tex]
so, you can choose the first choice confidently....
I hope you got
the idea