Let x represent the amount of money that Victoria had before she went for shopping.
Victoria spent one-fourth or her birthday money on clothes. It means that the amount she spent on shopping is 1/4 × x = x/4. Amount that she was having left would be x - x/4 = 3x/4
She received another 25$ a week later. The amount that she is having at this point will be 3x/4 + 25
The difference between 2x+16=14 than 2x+16=x+14 is that you would have to solve x in two different ways like finding the first equation another way than to the second equation ( I think ).