What's the law of indices

The long jump record, in feet, at a particular school can be modeled by f(x) = 19.6 + 2.5ln(x + 1) where x is the number of years since records began to be kept at the school. what is the record for the long jump 11 years after record started being kept? round your answer to the nearest tenth.

What is the value of x when x + 7 = 21?

Do you mind if you guys me with this question i’m on number 8