This question did not provide what is needed to be done. However, I understand what needs to be done.
Let's put the question in simple terms
Victoria and Karlie went shopping. Karlie spent three less than four times what Victoria spent. Together the girls spent $102.
So 3 less should be minus because when subtracting a number from another the result will be less than the original. And 4 times should be 4 times a number, but we don't know that number so we would put 4x, which is the same thing as 4(5), for example.
Put that in an equation format
Now, we can solve for "x". To find "x", we have to solve it the opposite way it was formed and the opposite operation. In other words, we are going to add 3 to both sides as our first step because "x" was multiplied to four first, then it subtracted 3 from x.
Add 3 to both sides
Divide both sides by 4