What is the value of x in the equation 2.5 -0.25 x= -3?

You start by taking the 2.5 over to the other side. This is a positive number so when you take it over it will become a negative.

2.5-0.25x = -3
     -0.25x =-3-2.5
     -0.25x=-5.5
    
now -0.25 is being multiplied to x, when you take it over to the other side, it becomes divide.

-0.25x = -5.5
        x = -5.5/-0.25
        x = 22