How can i do this? i don't understand

For part 1 you would say the expression is:
I-3 because an expression does not have an equal sign and ingrid swam 3 laps less than holly
For Part 2, you would substitute 25 into l, so it would be 25-3 which equals 22
Hope this helps.

/-3= laps Ingrid swam and to get the answer to part 2 just subtract 25 - 3