course operating system

please help me

solve the qeustion her not at book or camscanner please

Problem2 (40 pts) Given 3 concurrent processes P1, P2 and P3, we suppose that initially the share variable x =4. a) List all the possible values for x. (15 pts) b) Use one or more semaphores (use primitives signal and wait) in order to get x=13. (15 pts) c) Can we use only one semaphore to get x=11? Explain your answer. (10 pts) P1 P2 P3 XX-2: x=x*3