Let J be the number of points Jaylen scored, and T be the number of points Trevor scored. We have two pieces of information, which are enough to determine the values of the unknowns, because there are two of them (you need as many equations as unknowns).
The first thing we're told is that they scored 485 together, so you have
[tex] J+T=485 [/tex]
Then we know that Jaylen scored 25 points less than Trevor, which means
[tex] J = T-25 [/tex]
Substitute this expression for J in the first equation to get
[tex] J+T=485 \iff (T-25)+T=485 \iff 2T=510 \iff T = 255 [/tex]
So, now that we know that Trevor scored 255 points, we can easily calculate Jaylen's score:
[tex] J = T-25 = 255-25 = 230 [/tex]
