Aboy spent 2/3 money on book store,1/3 money on craft store and has left $8. how much money he has at first?

Suppose a pendulum is l meters long. the time,t,in seconds that it tales to swing back and forth once is given by t=2.01

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)