What is the answer to the solution?

- 4(6-1) = 12
- 24-48 = 12
- 4r = 36
r = -9

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

Can someone check if i did this correct. it’s number 4 if you’re wondering.

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums, 28 play drums, 18 play the guitar. what is the probability that the applicant who gets the job plays drums or guitar?