If pr = 4x – 2 and rs = 3x – 5, which expression represents ps?

You can use those 2 expressions Like vectors:
PR + RS = PS
4x - 2 + 3x - 5
Then you add the variables alone, then the numbers alone, and you get:
PS = 7x - 7
You can factories it too: 7(x-1)

Hope this Helps! :)