What is the square root of -1?

In the pendulum formula t=2pi. read the problem on the picture ! ; $; $; ! ; ! ; ! ; )$; ! ; ! ; ! ; $; $; $! ; ! ; ); $; $$

Find the value. a. 0.003 b. 0.03 c. 0.3 d. 3

Jermaine has t subway tokens. karen has 4 more subway tokens than jermaine. raul has 5 fewer subway tokens than jermaine. which expression represents the ratio of karen's tokens to raul's tokens