July 14th, 2019, 07:12 AM  #1 
Newbie Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1  I need help
I have two questions, they should be either true or false and I am asked to justify my answer. Thank you in advance. 
July 14th, 2019, 08:41 AM  #2 
Senior Member Joined: Jun 2019 From: USA Posts: 309 Thanks: 160 
Q1) A square matrix is singular if its determinant is zero (and vice versa). Find the determinant and see whether it equates to zero for all a, b, c. Q2) If I recall correctly, AB is equal to AB. If that's true, then B = (P/P)A = A. Last edited by skipjack; July 14th, 2019 at 08:13 PM. 
July 15th, 2019, 02:32 PM  #3 
Newbie Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 
Thank you so much for the help!

July 16th, 2019, 07:37 PM  #4 
Newbie Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 
Hello, for Q1) My friend had the solution below: How did he come to this solution? I have tried to calculate the determinant but the unknowns made it a headache for me. 
July 16th, 2019, 08:42 PM  #5  
Senior Member Joined: Sep 2015 From: USA Posts: 2,585 Thanks: 1430  Quote:
 
July 17th, 2019, 03:31 AM  #6 
Newbie Joined: Jul 2019 From: Saudi Arabia Posts: 4 Thanks: 1 
Thank you Boss!
